Hydroconversion processes employing multi-metallic catalysts and method for making thereof

ABSTRACT

A catalyst precursor composition and methods for making such catalyst precursor are disclosed. The catalyst precursor comprises at least a Promoter metal selected from Group VIII, Group IIB, Group IIA, Group IVA and combinations thereof, at least one Group VIB metal, at least one organic, oxygen-containing ligand, and a cellulose-containing material. Catalysts prepared from the sulfidation of such catalyst precursors are used in the hydroprocessing of hydrocarbon feeds. In one embodiment, the sulfidation is carried out by contacting the catalyst precursor with hydrogen and a sulfur containing compound, wherein the contacting is carried out ex-situ. Catalysts prepared from such catalyst precursors have a fouling rate of less than 8° F. (4.4° C.) per 1000 hour.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit under 35 USC 119 of U.S. ProvisionalPatent Application Nos. 60/984,240; 60/984,221; 60/984,195; 60/984,353;and 60/984,363, all with a filing date of Oct. 31, 2007. Thisapplication claims priority to and benefits from the foregoing, thedisclosures of which are incorporated herein by reference.

TECHNICAL FIELD

The invention relates generally to a hydroprocessing catalyst precursor,processes for preparing the catalyst precursor, multi-metallic catalystsprepared using the catalyst precursor, and hydroconversion processesemploying the multi-metallic catalysts.

BACKGROUND

The petroleum industry is increasingly turning to heavy crudes, resids,coals and tar sands as sources for feedstocks. Feedstocks derived fromthese heavy materials contain more sulfur and nitrogen than feedstocksderived from more conventional crude oils, requiring a considerableamount of upgrading in order to obtain usable products therefrom. Theupgrading or refining generally being accomplished by hydrotreatingprocesses, i.e., treating with hydrogen of various hydrocarbonfractions, or whole heavy feeds, or feedstocks, in the presence ofhydrotreating catalysts to effect conversion of at least a portion ofthe feeds to lower molecular weight hydrocarbons, or to effect theremoval of unwanted components, or compounds, or their conversion toinnocuous or less undesirable compounds.

Hydrotreating is well known in the art and typically requires treatingthe petroleum streams with hydrogen in the presence of a supported orunsupported catalyst at hydrotreating conditions. Supported catalystsare usually comprised of at least one Group VIB metal with one or moreGroup VIII metals as promoters on a refractory support, such as alumina.Hydrotreating catalysts that are particularly suitable forhydrodesulphurization, hydrodearomatization, as well ashydrodenitrogenation, generally contain molybdenum and/or tungstenpromoted with a metal such as cobalt, nickel, iron, or a combinationthereof. Cobalt promoted molybdenum on alumina catalysts are most widelyused when the limiting specifications are hydrodesulphurization. Nickelpromoted molybdenum on alumina catalysts are the most widely used forhydrodenitrogenation, partial aromatic saturation, as well ashydrodesulphurization.

Unsupported mixed Group VIII and Group VIB metal catalysts and catalystprecursors used for hydroconversion processes are known in the art asdisclosed in U.S. Pat. Nos. 2,238,851; 5,841,013; 6,156,695; 6,566,296and 6,860,987, amongst others.

Hydrotreating catalysts based on group IIB metals such as zinc were oneof the first base metal hydrotreating catalysts invented, and weredescribed in U.S. Pat. Nos. 1,922,499; 1,932,673; and 1,955,829.However, U.S. Pat. No. 4,698,145 teaches that group VIB metals basedcatalyst exhibit performance superior to group IIB metals basedcatalysts. Hydrotreating catalysts based on group IVA metals such as tinor lead were described U.S. Pat. Nos. 4,560,470 and 5,872,073.

Unsupported mixed Group IIB and Group VIB metal catalysts and catalystprecursors are known in the art. Methods for making catalyst precursorsand catalyst precursor compositions in the form of oxides of a Group IIBmetal and molybdenum and tungsten are taught in, for example, U.S. Pat.Nos. 1,932,673 and 1,955,829. Sulfided hydrogenation catalysts ofmolybdenum and tungsten are also known. U.S. Pat. No. 4,698,145 teachesthe process of making a sulfided catalyst with ammonium thio salts ofGroup VIB metals such as molybdenum or tungsten and salts of zinc in thepresence of a nitrogen containing additive. Unsupported mixed group IVAand group VIB metal catalysts and catalyst precursors are also known inthe art. These are made from the chlorides and sulfides in a multistepsynthesis as described in, for example, U.S. Pat. Nos. 4,560,470 and5,872,073.

As the environmental impact of effluents or water disposal fromindustries has become increasingly scrutinized, there is a need to limitthe use of toxic materials to the greatest extent possible. In theprocess of making catalyst precursors in the prior art, chelating agentssuch as ethylene diamine(tetra)acetic acid (EDTA), hydroxyethylenediamine triacetic acid, and diethylene triamine pentaacetic acid, etc.are employed. These materials are far from environmentally benign.

Under the reaction conditions employed in hydrotreating processes,catalyst performance, over time on stream, tends to become fouled withcarbon deposits, especially when the feedstock includes the heavier,more refractory fractions of hydrocarbon, S and N species in the heaviercrude oil. The accumulation of such deposits tends to reduce thecatalyst activity. Thus, catalyst average temperature (or C.A.T.) needsto be raised gradually in order to maintain product quality, such as theN concentration in the upgraded product. The rate of C.A.T. being raisedper unit time is defined as the fouling rate of catalyst.

Catalyst performance depends on a number of factors. For some catalysts,an important factor is the partial pressure of hydrogen employed in theprocess. A low pressure process can be generally described as having apressure of less than 600 psig, and in one embodiment, between 400 to600 psig. In a very low to low pressure hydroconversion process, someunsupported multi-metallic catalysts in the prior art have relativeactivity that is about ˜⅓ of the activity at moderate to high pressureprocess (2000 to 3000 psig and elevated temperatures generally rangingupward from 650° F.). Multi-metallic catalysts in the prior art are notsuitable for use in low pressure reactors of 300-400 psi due to theirlow activity.

There is a need for improved hydrodesulfurization (HDS),hydrodearomatization (HDA) and hydrodenitrogenation (HDN) catalystshaving the appropriate morphology, structure, and optimum catalyticactivity for high yield conversions of lower grade hydrocarbonfeedstocks to higher value products. There is a need for a process formaking such improved catalysts. There is still a need for chelatingagents in the manufacture of catalyst precursors that are less toxic ormore environmentally friendly or biodegradable without impairingperformance in hydroprocessing catalysis. There is a need for catalystswith improved fouling resistance characteristics. There is also a needfor catalysts that perform satisfactorily even in low pressurehydroconversion processes.

SUMMARY OF THE INVENTION

In one aspect, the invention relates to a catalyst having a fouling rateof less than 8° F. (4.4° C.) per 1000 hour, wherein the catalyst isprepared by sulfiding a catalyst precursor composition obtained byco-precipitating at reaction conditions to form a precipitate at least aPromoter metal compound in solution; at least a Group VIB metal compoundin solution; and at least an organic oxygen containing chelating ligandin solution.

In another aspect, the catalyst when employed in a fixed bedhydroprocessing system having at least two layers of catalysts andwherein the catalyst comprises from 10-80 vol. % of the layered catalystsystem, provides a fouling rate of less than 30° F. (16.7° C.) per 1000hour for the layered catalyst system.

In one aspect, the invention relates to a catalyst precursor compositionof the formula A_(v)[(M^(P))(OH)_(x)(L)^(n) _(y)]_(z)(M^(VIB)O₄,obtained by co-precipitation at reaction conditions forming aprecipitate or cogel with at least one of a Promoter metal M^(P)selected from Group VIII, Group IIA, Group IIB, and VIB metal compoundshaving an oxidation state of +2 or 4+, at least one of a Group VIB metalcompound M^(VIB) having an oxidation state of +6, at least one of anorganic, oxygen-containing ligand L having a charge n<=0 and an LD50rate of >500 mg/Kg as single oral dose to rats; wherein A is at leastone of an alkali metal cation, an ammonium, an organic ammonium and aphosphonium cation, M^(P):M^(VIB) has an atomic ratio of 100:1 to 1:100;v−2+P*z−x*z +n*y*z=0; and 0≦y≦−P/n; 0≦x≦P; 0≦v≦2; 0≦z; and wherein acatalyst prepared from the catalyst precursor composition has a foulingrate of less than 8° F. (4.4° C.) per 1000 hour.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a powder X-ray diffraction pattern of an embodiment of acatalyst precursor in the prior art (Ni/Mo/W).

FIG. 2 shows the powder X-ray diffraction pattern of an embodiment of acatalyst precursor compound (based on Ni/Mo/W/maleate).

FIG. 3 shows powder X-ray diffraction pattern of a second embodiment ofa catalyst precursor compound (based on Co/Mo/W/maleate).

FIG. 4 shows powder X-ray diffraction pattern of a comparative catalystprecursor without maleic acid as a chelating agent (based onCo/Mo/W/maleate).

FIG. 5 is a graph comparing the catalyst average temperature (C.A.T.)profile of an embodiment of a multi-metallic catalyst employing thecatalyst precursor compound of the invention vs. a catalyst system inthe prior art. The C.A.T. profile here is the C.A.T. required over timeon stream to maintain 20 wtppm nitrogen in the upgraded product.

FIG. 6 is a powder X-ray diffraction pattern of a third embodiment of acatalyst precursor compound (based on Zn—Mo—W-maleate).

FIG. 7 is a powder X-ray diffraction pattern of a fourth embodiment of acatalyst precursor compound (also based on Zn—Mo—W).

FIG. 8 shows powder X-ray diffraction pattern of a fifth embodiment of acatalyst precursor compound (based on Sn/Mo/W/maleate).

FIG. 9 shows the powder X-ray diffraction pattern of a comparativecatalyst precursor compound (Sn/Mo/W without chelating agent).

DETAILED DESCRIPTION

The following terms will be used throughout the specification and willhave the following meanings unless otherwise indicated.

SCF/BBL (or scf/bbl, or scfb or SCFB) refers to a unit of standard cubicfoot of gas (N₂, H₂, etc.) per barrel of hydrocarbon feed.

LHSV means liquid hourly space velocity.

C.A.T. means the catalyst average temperature, based on multiplereadings in the catalyst bed.

The Periodic Table referred to herein is the Table approved by IUPAC andthe U.S. National Bureau of Standards, an example is the Periodic Tableof the Elements by Los Alamos National Laboratory's Chemistry Divisionof October 2001.

The term “Group VIB” or “Group VIB metal” refers to chromium,molybdenum, tungsten, and combinations thereof in their elemental,compound, or ionic form.

The term “Group IIB” or “Group IIB metal” refers to zinc, cadmium,mercury and combinations thereof in their elemental, compound, or ionicform.

The term “Group IIA” or “Group IIA metal” refers to beryllium,magnesium, calcium, strontium, barium, radium, and combinations thereofin their elemental, compound, or ionic form.

The term “Group IVA” or” “Group IVA metal” refers to germanium, tin orlead, and combinations thereof in their elemental, compound, or ionicform.

The term “Group VIII” or “Group VIII metal” refers to iron, cobalt,nickel, ruthenium, rhenium, palladium, osmium, iridium, platinum, andcombinations thereof in their elemental, compound, or ionic form.

As used herein, the term M^(P), or “Promoter metal” means any of: atleast one of Group VIII metals; at least one of Group IIB metals; atleast one of Group IIA metals; at least of one of Group IVA metals; acombination of different Group IIB metals; a combination of differentGroup IIA metals; a combination of different Group IVA, IIA, IIB, orVIII metals; a combination of at least a Group IIB metal and at least aGroup IVA metal; a combination of at least a Group IIB metal and atleast a group VIII metal; a combination of at least a Group IVA metaland at least a group VIII metal; a combination of at least a Group IIBmetal, at least a Group IVA metal and at least a group VIII metal; andcombinations at least two metals, with the individual metal being fromany of Group VIII, Group IIB, Group IIA, and Group IVA metals.

As used herein, the phrases “one or more of” or “at least one of” whenused to preface several elements or classes of elements such as X, Y andZ or X₁-X_(n), Y₁-Y_(n) and Z₁-Z_(n), is intended to refer to a singleelement selected from X or Y or Z, a combination of elements selectedfrom the same common class (such as X₁ and X₂), as well as a combinationof elements selected from different classes (such as X₁, Y₂ and Zn).

As used herein, “hydroconversion” or “hydroprocessing” is meant anyprocess that is carried out in the presence of hydrogen, including, butnot limited to, methanation, water gas shift reactions, hydrogenation,hydrotreating, hydrodesulphurization, hydrodenitrogenation,hydrodemetallation, hydrodearomatization, hydroisomerization,hydrodewaxing and hydrocracking including selective hydrocracking.Depending on the type of hydroprocessing and the reaction conditions,the products of hydroprocessing can show improved viscosities, viscosityindices, saturates content, low temperature properties, volatilities anddepolarization, etc.

As used herein, the term “catalyst precursor” refers to a compoundcontaining at least a Promoter metal selected from Group VIII, GroupIIB, Group IIA, Group IVA and combinations thereof (i.e., one or moreGroup VIII metals, one or more Group IIB metals, one or more Group IIAmetals, one or more Group IVA metals, and combinations thereof), atleast a Group VIB metal; at least a hydroxide; and one or more organicoxygen-containing ligands, and which compound can be catalyticallyactive after sulfidation as a hydroprocessing catalyst.

As used herein, the term “charge-neutral” refers to the fact that thecatalyst precursor carries no net positive or negative charge. The term“charge-neutral catalyst precursor” can sometimes be referred to simplyas “catalyst precursor.”

As used herein, the term “ammonium” refers to a cation with the chemicalformula NH₄ ⁺ or to organic nitrogen containing cations, such as organicquaternary amines.

As used herein, the term “phosphonium” refers to a cation with thechemical formula PH₄ ⁺ or to organic phosphorus-containing cations.

The term oxoanion refers to monomeric oxoanions and polyoxometallates.

As used herein, the term “mixture” refers to a physical combination oftwo or more substances. The “mixture” can be homogeneous orheterogeneous and in any physical state or combination of physicalstates.

The term “reagent” refers to a raw material that can be used in themanufacture of the catalyst precursor of the invention. When used inconjunction with a metal, the term “metal” does not mean that thereagent is in the metallic form, but is present as a metal compound.

As used herein the term “carboxylate” refers to any compound containinga carboxylate or carboxylic acid group in the deprotonated or protonatedstate.

As used herein, the term “ligand” may be used interchangeably with“chelating agent” (or chelator, or chelant), referring to an additivethat combines with metal ions, e.g., Group VIB and/or Promoter metals,forming a larger complex, e.g., a catalyst precursor.

As used herein, the term “organic” means containing carbon, and whereinthe carbon can be from biological or non-biological sources.

As used herein, the term “organic oxygen-containing ligand” refers toany compound comprising at least one carbon atom, at least one oxygenatom, and at least one hydrogen atom wherein said oxygen atom has one ormore electron pairs available for co-ordination to the Promoter metal(s)or Group VIB metal ion. In one embodiment, the oxygen atom is negativelycharged at the pH of the reaction. Examples of organic oxygen-containingligands include, but are not limited to, carboxylic acids, carboxylates,aldehydes, ketones, the enolate forms of aldehydes, the enolate forms ofketones, hemiacetals, and the oxo anions of hemiacetals.

The term “cogel” refers to a hydroxide co-precipitate (or precipitate)of at least two metals containing a water rich phase. “Cogelation”refers to the process of forming a cogel or a precipitate.

As used herein, the term “biodegradable” refers to a material thatreadily degrades under aerobic and/or anaerobic conditions in thepresence of bacteria, fungi, algae, and/OR other microorganisms tocarbon dioxide/methane, and/or water and biomass, although materialscontaining heteroatoms can also yield other products such as ammonia orsulfur dioxide. The term includes degradation by exposure to ultravioletlight, sunlight, temperatures and pressures normally found in thebiosphere. The time required for degradation is not, however, fixed.Preferably, degradation takes place quickly after exposure toenvironmental conditions such as in a landfill, but even if degradationtakes more than a trivial amount of time, the material can still beconsidered “readily biodegradable.”

As used herein, the term “non-toxic” refers to the requirements of theLD 50 Oral Toxicity Test. LD means “lethal dosage.” LD50 is the amountof a material, given all at once, causes the death of 50% (one half) ofa group of test animals. LD-50 measures the short-term poisoningpotential (acute toxicity) of a material with the testing being donewith smaller animals such as rats and mice (in mg/Kg).

As used herein, a non-toxic material means the material has an LD50 ofgreater than 500 mg/Kg (as single oral dose to rats).

As used herein, fouling rate means the rate at which the hydroconversionreaction temperature needs to be raised per unit time, e.g., ° F. per1000 hours, in order to maintain a given hydrodenitrogenation rate(e.g., nitrogen level in the upgraded products, desiredhydrodenitrogenation rate, etc.).

As used herein, the fouling rate is measured in a hydrodenitrogenation(HDN) system with a single catalyst, employing a vacuum gas oil (VGO)having properties of Table 3 as the feed, including 4.6 CSt viscosity at100° C., 0.928 g/cc density, 178-495° C. boiling range, and 1.66hydrogen to carbon atomic ratio; and process condition of 370-425° C.,10 MPa pressure, 1.0 h⁻¹ LHSV, and hydrogen flow rate of 5000 scfb, withthe HDN target of an organic nitrogen level of 20 ppm in the totalamount of upgraded liquid products.

As used herein, a layered catalyst system fouling rate means the ratemeasured for an entire catalyst system having multiple layers ofdifferent catalysts. The rate is measured in a hydrodenitrogenation(HDN) run with vacuum gas oil (VGO) having properties of Table 3 as thefeed, including 4.6 CSt viscosity at 100° C., 0.928 g/cc density,178-495° C. boiling range, and 1.66 hydrogen to carbon atomic ratio; andprocess condition of 370-425° C., 10 MPa pressure, 1.0 h⁻¹ LHSV, andhydrogen flow rate of 5000 scfb, with the HDN target of having anitrogen level of 20 ppm in the upgraded products.

As used herein, 700° F.+ conversion rate refers to the conversion ofvacuum gas oil (VGO) feedstock to less than 700° F. (371.° C.) boilingpoint materials in a hydroconversion process, computed as (100%*(wt. %boiling above 700° F. materials in feed−wt. % boiling above 700° F.materials in products)/wt. % boiling above 700° F. materials in feed)).In one embodiment, the vacuum gas oil (VGO) feedstock has properties ofTable 3 as the feed, including 4.6 CSt viscosity at 100° C., 0.928 g/ccdensity, 178-495° C. boiling range, and 1.66 hydrogen to carbon atomicratio. The hydroconversion process condition includes temperature370-425° C., 10 MPa pressure, 1.0 h⁻¹ LHSV, and hydrogen flow rate of5000 scfb.

In one aspect, the invention relates to a catalyst precursor which canbe converted into a catalyst for use in hydrodesulfurization (HDS),hydrodearomatization (HDA), and hydrodenitrification (HDN), e.g.,Promoter metal(s)/Group VIB sulfided metal catalyst. In one embodiment,the porosity of the Promoter metal(s)/Group VIB sulfided metal catalystscan be advantageously tuned with the use of Promoter metal hydroxidesand organic oxygen-containing ligands in the synthesis of the catalystprecursor and with cellulose-containing additives during the forming ofthe precursor into an extrudate. Upon sulfidation of the catalystprecursor to form the active catalyst, the properties of the activecatalyst is enhanced with respect to traditional sulfided zinc or cobaltmolybdenum, sulfided nickel molybdenum, tungsten, and molybdotungstencatalysts.

Catalyst Precursor Formula: In one embodiment, the charge-neutralcatalyst precursor composition is of the general formulaA_(v)[(M^(P))(OH)_(x)(L)^(n) _(y)]_(z)(M^(VIB)O₄), wherein:

A is one or more monovalent cationic species. In one embodiment, A is atleast one of an alkali metal cation, an ammonium, an organic ammoniumand a phosphonium cation;

M^(P) is at least a Promoter metal with an oxidation state of either +2or +4 depending on the Promoter metal(s) being employed. M^(P) isselected from Group VIII, Group IIB, Group IIA, Group IVA andcombinations thereof. In one embodiment, M^(P) is at least a Group VIIImetal, M^(P) has an oxidation state of +2. In another embodiment, M^(P)is selected from Group IIB, Group IVA and combinations thereof.

L is one or more oxygen-containing ligands, and L has a neutral ornegative charge n<=0;

M^(VIB) is at least a Group VIB metal having an oxidation state of +6;

M^(P):M^(VIB) has an atomic ratio between 100:1 and 1:100;

v−2+P*z−x*z+n*y*z=0; and

0≦y≦−P/n; 0≦x≦P; 0≦v≦2; 0≦z.

In one embodiment, A is selected from carboxylates, carboxylic acids,aldehydes, ketones, the enolate forms of aldehydes, the enolate forms ofketones, and hemiacetals, and combinations thereof.

In one embodiment, A is selected from monovalent cations such as NH₄ ⁺,other quaternary ammonium ions, organic phosphonium cations, alkalimetal cations, and combinations thereof.

In one embodiment where both molybdenum and tungsten are used as theGroup VIB metals, the molybdenum to tungsten atomic ratio (Mo:W) is inthe range of about 10:1 to 1:10. In another embodiment, the ratio ofMo:W is between about 1:1 and 1:5. In an embodiment where molybdenum andtungsten are used as the Group VIB metals, the charge-neutral catalystprecursor is of the formula A_(v)[(M^(P))(OH)_(x)(L)^(n)_(y)]_(z)(Mo_(t)W_(t′)O₄). In yet another embodiment, where molybdenumand tungsten are used as the Group VIB metals, chromium can besubstituted for some or all of the tungsten with the ratio of (Cr+W):Mois in the range of about 10:1 to 1:10. In another embodiment, the ratioof (Cr+W):Mo is between 1:1 and 1:5. In an embodiment where molybdenum,tungsten, and chromium are the Group VIB metals, the charge-neutralcatalyst precursor is of the formula A_(v)[(M^(P))(OH)_(x)(L)^(n)_(y)]_(z)(Mo_(t)W_(t′)Cr_(t″)O₄).

In one embodiment, the Promoter metal M^(P) is at least a Group VIIImetal with M^(P) having an oxidation state of +2 and the catalystprecursor of the formula A_(v)[(M^(P))(OH)_(x)(L)^(n)_(y)]_(z)(M^(VIB)O₄)to have (v−2+2z−x*z+n*y*z)=0

In one embodiment where the Promoter metal M^(P) is a mixture of twoGroup VIII metals such as Ni and Co. In yet another embodiment, M^(P) isa combination of three metals such as Ni, Co and Fe.

In one embodiment where M^(P) is a mixture of two group IIB metals suchas Zn and Cd, the charge-neutral catalyst precursor is of the formulaA_(v)[(Zn_(a)Cd_(a′))(OH)_(x)(L)_(y)]_(z)(M^(VIB)O₄). In yet anotherembodiment, M^(P) is a combination of three metals such as Zn, Cd andHg, the charge-neutral catalyst precursor is of the formulaA_(v)[(Zn_(a)Cd_(a′)Hg_(a″))(OH)_(x)(L)^(n) _(y)]_(z)(M^(VIB)O₄).

In one embodiment wherein M^(P) is a mixture of two Group IVA metalssuch as Ge and Sn, the charge-neutral catalyst precursor is of theformula A_(v)[(Ge_(b),Sn_(b′)) (OH)_(x)(L)^(n) _(y)]_(z)(M^(VIB)O₄). Inanother embodiment wherein M^(P) is a combination of three Group IVAmetals such as Ge, Sn, and Pb, the charge-neutral catalyst precursor isof the formula A_(v)[(Ge_(b)Sn_(b′)Pba_(b″))(OH)_(x)(L)^(n)_(y)]_(z)(M^(VIB)O₄).

Promoter Metal Component M^(P): In one embodiment, the source for thePromoter metal (M^(P)) compound is in a solution state, with the wholeamount of the Promoter metal compound dissolved in a liquid to form ahomogeneous solution. In another embodiment, the source for the Promotermetal is partly present as a solid and partly dissolved in the liquid.In a third embodiment, it is completely in the solid state.

The Promoter metal compound M^(P) can be a metal salt or mixtures ofmetal salts selected from nitrates, hydrated nitrates, chlorides,hydrated chlorides, sulphates, hydrated sulphates, carbonates, formates,acetates, oxalates, citrates, maleates, fumarate, phosphates,hypophosphites, and mixtures thereof.

In one embodiment, the Promoter metal M^(P) is a nickel compound whichis at least partly in the solid state, e.g., a water-insoluble nickelcompound such as nickel carbonate, nickel hydroxide, nickel phosphate,nickel phosphite, nickel formate, nickel fumarate, nickel sulphide,nickel molybdate, nickel tungstate, nickel oxide, nickel alloys such asnickel-molybdenum alloys, Raney nickel, or mixtures thereof

In one embodiment, the Promoter metal M^(P) is selected from the groupof IIB and VIA metals such as zinc, cadmium, mercury, germanium, tin orlead, and combinations thereof, in their elemental, compound, or ionicform. In yet another embodiment, the Promoter metal M^(P) furthercomprises at least one of Ni, Co, Fe and combinations thereof, in theirelemental, compound, or ionic form.

In one embodiment, the Promoter metal compound is a zinc compound whichis at least partly in the solid state, e.g., a zinc compound poorlysoluble in water such as zinc carbonate, zinc hydroxide, zinc phosphate,zinc phosphite, zinc formate, zinc fumarate, zinc sulphide, zincmolybdate, zinc tungstate, zinc oxide, zinc alloys such aszinc-molybdenum alloys.

In an embodiment, the Promoter metal is a Group IIA metal compound,selected from the group of magnesium, calcium, strontium and bariumcompounds which are at least partly in the solid state, e.g., awater-insoluble compound such as a carbonate, hydroxide, fumarate,phosphate, phosphite, sulphide, molybdate, tungstate, oxide, or mixturesthereof.

In one embodiment, the Promoter metal compound is a tin compound whichis at least partly in the solid state, e.g., a tin compound poorlysoluble in water such as stannic acid, tin phosphate, tin formate, tinacetate, tin molybdate, tin tungstate, tin oxide, tin alloys such astin-molybdenum alloys.

Group VIB Metal Component: The Group VIB metal (M^(VIB)) compound can beadded in the solid, partially dissolved, or solution state. In oneembodiment, the Group VIB metal compound is selected from molybdenum,chromium, tungsten compounds, and combinations thereof. Examples of suchcompounds include, but are not limited to, alkali metal, alkaline earth,or ammonium metallates of molybdenum, tungsten, or chromium, (e.g.,ammonium tungstate, meta-, para-, hexa-, or polytungstate, ammoniumchromate, ammonium molybdate, iso-, peroxo-, di-, tri-, tetra-, hepta-,octa-, or tetradecamolybdate, alkali metal heptamolybdates, alkali metalorthomolybdates, or alkali metal isomolybdates), ammonium salts ofphosphomolybdic acids, ammonium salts of phosphotunstic acids, ammoniumsalts of phosphochromic acids, molybdenum (di- and tri) oxide, tungsten(di- and tri) oxide, chromium or chromic oxide, molybdenum carbide,molybdenum nitride, aluminum molybdate, molybdic acid, chromic acid,tungstic acid, Mo—P heteropolyanion compounds, Wo—Si heteropolyanioncompounds, W—P heteropolyanion compounds. W—Si heteropolyanioncompounds, Ni—Mo—W heteropolyanion compounds, Co—Mo—W heteropolyanioncompounds, or mixtures thereof, added in the solid, partially dissolved,or solute state.

Chelating Agent (Ligand) L: In one embodiment, the catalyst precursorcomposition comprises at least a non-toxic organic oxygen containingligand with an LD50 rate (as single oral dose to rats) of greater than500 mg/Kg. In a second embodiment, the organic oxygen containing ligandL has an LD50 rate of >700 mg/Kg. In a third embodiment, organic oxygencontaining chelating agent has an LD50 rate of >1000 mg/Kg. As usedherein, the term “non-toxic” means the ligand has an LD50 rate (assingle oral dose to rats) of greater than 500 mg/Kg. As used herein theterm “at least an organic oxygen containing ligand” means thecomposition may have more than one organic oxygen containing ligand insome embodiments, and some of the organic oxygen containing ligand mayhave an LD50 rate of <500 mg/Kg, but at least one of the organic oxygencontaining ligands has an LD50 rate of >500 mg/Kg.

In one embodiment, the oxygen-containing chelating agent L is selectedfrom the group of non-toxic organic acid addition salts such as formicacid, acetic acid, propionic acid, maleic acid, fumaric acid, succinicacid, tartaric acid, citric acid, oxalic acid, glyoxylic acid, asparticacid, alkane sulfonic acids such as methane sulfonic acid and ethanesulfonic acid, aryl sulfonic acids such as benzene sulfonic acid andp-toluene sulfonic acid and arylcarboxylic acids such as benzoic acid.In one embodiment, the oxygen-containing chelating agent L is maleicacid (LD of 708 mg/kg).

In one another embodiment, the non-toxic chelating agent L is selectedfrom the group of glycolic acid (having an LD50 of 1950 mg/kg), lacticacid (LD50 of 3543 mg/kg), tartaric acid (LD50 of 7500 mg/kg), malicacid (LD50 of 1600 mg/kg), citric acid (LD50 of 5040 mg/kg), gluconicacid (LD50 of 10380 mg/kg), methoxy-acetic acid (LD50 of 3200 mg/kg),ethoxy-acetic acid (LD50 of 1292 mg/kg), malonic acid (LD 50 of 1310mg/Kg), succinic acid (LD 50 of 500 mg/kg), fumaric acid (LD50 of 10700mg/kg), and glyoxylic (LD 50 of 3000 mg/kg). In yet embodiment thenon-toxic chelating agent is selected from the group of organic sulfurcompounds including but not limited to mercapto-succinic acid (LD 50 of800 mg/kg) and thio-diglycolic acid (LD 50 of 500 mg/kg).

In yet another the oxygen containing ligand L is a carboxylatecontaining compound. In one embodiment, the carboxylate compoundcontains one or more carboxylate functional groups. In yet anotherembodiment, the carboxylate compound comprises monocarboxylatesincluding, but not limited to, formate, acetate, propionate, butyrate,pentanoate, and hexanoate and dicarboxylates including, but not limitedto, oxalate, malonate, succinate, glutarate, adipate, malate, maleate,fumarate, and combinations thereof In a fourth embodiment, thecarboxylate compound comprises maleate.

The organic oxygen containing ligands can be mixed with the Promotermetal containing solution or mixture, the Group VIB metal containingsolution or mixture, or a combination of the Promoter metal and GroupVIB metal containing precipitates, solutions, or mixtures. The organicoxygen containing ligands can be in a solution state, with the wholeamount of the organic oxygen containing ligands dissolved in a liquidsuch as water. The organic oxygen containing ligands can be partiallydissolved and partially in the solid state during mixing with thePromoter metal(s), Group VIB metal(s), and combinations thereof.

Diluent Component: The term diluent may be used interchangeably withbinder. The use of diluent is optional in the making of the catalystprecursor.

In one embodiment, a diluent is included in the process for making thecatalyst precursor composition. Generally, the diluent material to beadded has less catalytic activity than the catalyst prepared from thecatalyst precursor composition (without the diluent) or no catalyticactivity at all. Consequently in one embodiment, by adding a diluent,the activity of the catalyst can be reduced. Therefore, the amount ofdiluent to be added in the process generally depends on the desiredactivity of the final catalyst composition. Diluent amounts from 0-95wt. % of the total composition can be suitable, depending on theenvisaged catalytic application.

The diluent can be added to the Promoter metal component(s), Promotermetal containing mixtures, Group VIB metal(s) or metal containingmixtures either simultaneously or one after the other. Alternatively,the Promoter metal and Group VIB metal mixtures can be combinedtogether, and subsequently a diluent can be added to the combined metalmixtures. It is also possible to combine part of the metal mixtureseither simultaneously or one after the other, to subsequently add thediluent and to finally add the rest of the metal mixtures eithersimultaneously or one after the other. Furthermore, it is also possibleto combine the diluent with metal mixtures in the solute state and tosubsequently add a metal compound at least partly in the solid state.The organic oxygen containing ligand is present in at least one of themetal containing mixtures.

In one embodiment, the diluent is composited with a Group VIB metaland/or a Promoter metal, prior to being composited with the bulkcatalyst precursor composition and/or prior to being added during thepreparation thereof. Compositing the diluent with any of these metals inone embodiment is carried out by impregnation of the solid diluent withthese materials.

Diluent materials include any materials that are conventionally appliedas a diluent or binder in hydroprocessing catalyst precursors. Examplesinclude silica, silica-alumina, such as conventional silica-alumina,silica-coated alumina and alumina-coated silica, alumina such as(pseudo)boehmite, or gibbsite, titania, zirconia, cationic clays oranionic clays such as saponite, bentonite, kaoline, sepiolite orhydrotalcite, or mixtures thereof In one embodiment, binder materialsare selected from silica, colloidal silica doped with aluminum,silica-alumina, alumina, titanic, zirconia, or mixtures thereof

These diluents can be applied as such or after peptization. It is alsopossible to apply precursors of these diluents that, during the process,are converted into any of the above-described diluents. Suitableprecursors are, e g., alkali metal or ammonium aluminates (to obtain analumina diluent), water glass or ammonium- or acid-stabilized silicasols (to obtain a silica diluent), a mixture of aluminates and silicates(to obtain a silica alumina diluent), a mixture of sources of a di-,tri-, and/or tetravalent metal such as a mixture of water-soluble saltsof magnesium, aluminum and/or silicon (to prepare a cationic clay and/oranionic clay), chlorohydrol, aluminum sulfate, or mixtures thereof

Other Optional Components: If desired, other materials, including othermetals can be added in addition to the components described above. Thesematerials include any material that is added during conventionalhydroprocessing catalyst precursor preparation. Suitable examples arephosphorus compounds, borium compounds, additional transition metals,rare earth metals, fillers, or mixtures thereof. Suitable phosphoruscompounds include ammonium phosphate, phosphoric acid, or organicphosphorus compounds. Phosphorus compounds can be added at any stage ofthe process steps. Suitable additional transition metals that can beadded to the process steps include are, e.g., rhenium, ruthenium,rhodium, iridium, chromium, vanadium, iron, cobalt, nickel, zinc,platinum, palladium, cobalt, etc. In one embodiment, the additionalmetals are applied in the form of water-insoluble compounds. In anotherembodiment, the additional metals are added in the form of water solublecompounds. Apart from adding these metals during the process, it is alsopossible to composite the final catalyst precursor composition therewiththe optional materials. It is, e.g., possible to impregnate the finalcatalyst precursor composition with an impregnation solution comprisingany of these additional materials.

Methods for Making Hydroprocessing Catalyst precursor: The preparationmethod allows systematic varying of the composition and structure of thecatalyst precursor by controlling the relative amounts of the elements,the types of the reagents, and the length and severity of the variousreactions and reaction steps.

The order of addition of the reagents used in forming the catalystprecursor is not important. For example, organic oxygen containingligand can be combined with a mixture of Promoter metal(s) and Group VIBmetal(s) prior to precipitation or cogelation. The organic oxygencontaining ligand can be mixed with a solution of a Promoter metal, andthen added to a solution of one or more Group VIB metals. The organicoxygen containing ligand can be mixed with a solution of one or moreGroup VIB metals and added to a solution of one or more Promoter metals.

Forming a Precipitate or Cogel with Group VIB/Promoter Metals: In oneembodiment of the process, the first step is a precipitation orcogelation step, which involves reacting in a mixture the Promoter metalcomponent(s) in solution and the Group VIB metal component in solutionto obtain a precipitate or cogel. The precipitation or cogelation iscarried out at a temperature and pH which the Promoter metal compoundand the Group VIB metal compound precipitate or form a cogel. An organicoxygen containing ligand in solution or at least partially in solutionis then combined with the precipitate or cogel to form an embodiment ofthe catalyst precursor.

In an embodiment, the temperature at which the catalyst precursor isformed is between 50-150° C. If the temperature is below the boilingpoint of the protic liquid, such as 100° C. in the case of water, theprocess is generally carried out at atmospheric pressure. Above thistemperature, the reaction is generally carried out at increasedpressure, such as in an autoclave. In one embodiment, the catalystprecursor is formed at a pressure between 0 to 3000 psig. In a secondembodiment, between 100 to 1000 psig.

The pH of the mixture can be changed to increase or decrease the rate ofprecipitation or cogelation, depending on the desired characteristics ofthe product. In one embodiment, the mixture is kept at its natural pHduring the reaction step(s). In another embodiment, the pH is maintainedin the range of 0-12. In another embodiment, between 4-10. In a furtherembodiment, the pH ranges between 7-10. Changing the pH can be done byadding base or acid to the reaction mixture, or adding compounds, whichdecompose upon temperature increase into hydroxide ions or H⁻ ions thatrespectively increase or decrease the pH. Examples include urea,nitrites, ammonium hydroxide, mineral acids, organic acids, mineralbases, and organic bases.

In one embodiment, the reaction of Promoter metal component(s) iscarried out with water-soluble metal salts, e.g., zinc, molybdenum andtungsten metal salts. The solution can further comprise other Promotermetal component(s), e.g., cadmium or mercury compounds such as Cd(NO₃)₂or (CH₃CO₂)₂Cd, Group VIII metal components including cobalt or ironcompounds such as Co(NO₃)₂ or (CH₃CO₂)₂Co, as well as other Group VIBmetal component(s) such as chromium.

In one embodiment, the reaction of Promoter metal component(s) iscarried out with water-soluble tin, molybdenum and tungsten metal salts.The solution can further comprise other Group IVA metal component(s),e.g. lead compounds such as Pb(NO₃)₄ or (CH₃CO₂)₂Pb, as well as otherGroup VIB metal compounds such as chromium compounds.

The reaction is carried with the appropriate metal salts resulting inprecipitate or cogel combinations of zinc/molybdenum/tungsten,tin/molybdenum/tungsten, zinc/molybdenum, zinc/tungsten, tin/molybdenum,tin/tungsten, or zinc/tin/molybdenum/tungsten, ornickel/molybdenum/tungsten, cobalt/molybdenum/tungsten,nickel/molybdenum, nickel/tungsten, cobalt/molybdenum, cobalt/tungsten,or nickel/cobalt/molybdenum/tungsten. An organic oxygen containingligand can be added prior to or after precipitation or cogelation of thePromoter metal compounds and/or Group VIB metal compounds.

The metal precursors can be added to the reaction mixture in solution,suspension or a combination thereof. If soluble salts are added as such,they will dissolve in the reaction mixture and subsequently beprecipitated or cogeled. The solution can be heated optionally undervacuum to effect precipitation and evaporation of the water.

After precipitation or cogelation, the catalyst precursor can be driedto remove water. Drying can be performed under atmospheric conditions orunder an inert atmosphere such as nitrogen, argon, or vacuum. Drying canbe effected at a temperature sufficient to remove water but not removalof organic compounds. Preferably drying is performed at about 120° C.until a constant weight of the catalyst precursor is reached.

Forming a Precipitate with Optional Binder Component(s): In oneembodiment with the use of a binder, the binder components can be addedto the reaction mixture containing the metal precursors in solution,suspension or a combination thereof, forming precipitation orcogelation. The precipitate is subsequently dried to remove water.

In one embodiment with the use of magnesium aluminosilicate clay as abinder, a first reaction mixture is formed comprising a siliconcomponent, an aluminum component, a magnesium component, the Promotermetal compounds and/or Group VIB metal compounds. In one embodiment, thefirst reaction mixture is formed under ambient pressure and temperatureconditions. In one embodiment, the reaction is under a pressures rangingfrom 0.9 bar and 1.2 bar, and a temperature between about 0° C. and 100°C.

Examples of silicon components include, but are not limited to sodiumsilicate, potassium silicate, silica gels, silica sols, silica gels,hydronium- or ammonium-stabilized silica sols, and combinations thereof.Examples of aluminum components aluminum useful in the process of thepresent invention include, but are not limited to, sodium aluminate,potassium aluminate, aluminum sulfate, aluminum nitrate, andcombinations thereof. Examples of magnesium components useful in theprocess of the present invention include, but are not limited to,magnesium metal, magnesium hydroxide, magnesium halides, magnesiumsulfate, magnesium nitrate, and combinations thereof. In one embodiment,a sufficient amount of an acid is added to the mixture containing themetal precursors and the binder components to adjust the pH of themixture to about 1 to about 6, forming a first reaction mixture.

After the formation of the first reaction mixture, an alkali base isadded to form a second reaction mixture. Examples of alkali baseinclude, but are not limited to, ammonium hydroxide, sodium hydroxideand potassium hydroxide. Sufficient alkali base is added to the firstreaction mixture for the pH of the resulting second reaction mixturebetween about 7 to about 12. The second reaction mixture is then reactedfor sufficient time and at sufficient temperature to form a catalystprecursor incorporating at least a clay as a binder. In embodiments, thetime is at least one second. In a second embodiment, 15 minutes. A thirdembodiment, at least 30 minutes. The temperature of the second reactionmixture can range from about 0° C. to about 100° C. The reaction can bedone at ambient pressure, although higher or lower pressures are notexcluded.

In one embodiment with magnesium aluminosilicate clay as a binder, theratio of silicon to aluminum to magnesium can be expressed in terms ofelemental mole ratios: aSi:bAl:cMg. wherein “a” has a value from 3 to 8,“b” has a value from 0.6 to 1.6, and “c” has a value of from 3 to 6.

Characterization of the Catalyst precursor: Characterization of thecharge-neutral catalyst precursor can be performed using techniquesknown in the art, including, but not limited to, powder x-raydiffraction (PXRD), elemental analysis, surface area measurements,average pore size distribution, average pore volume. Porosity andsurface area measurements can be performed using BJH analysis underB.E.T. nitrogen adsorption conditions.

Characteristics of the Catalyst precursor: In one embodiment, thecatalyst precursor has an average pore volume of 0.05-5 ml/g asdetermined by nitrogen adsorption. In another embodiment, the averagepore volume is 0.1-4 ml/g. In a third embodiment, 0.1-3 ml/g.

In one embodiment, the catalyst precursor has a surface area of at least10 m²/g. In a second embodiment, a surface area of at least 50 m²/g. Ina third embodiment, a surface area of at least 150 m²/g.

In one embodiment, the catalyst precursor has an average pore size, asdefined by nitrogen adsorption, of 2-50 nanometers. In a secondembodiment, an average pore size of 3-30 nanometers. In a thirdembodiment, an average pore size of 4-15 nanometers.

In one embodiment with the inclusion of magnesium aluminosilicate clayas a binder, the catalyst precursor is a layered material composed of astack of elemental clay platelets.

Shaping Process: In one embodiment, the catalyst precursor compositioncan generally be directly formed into various shapes depending on theintended commercial use. These shapes can be made by any suitabletechnique, such as by extrusion, pelletizing, beading, or spray drying.If the amount of liquid of the bulk catalyst precursor composition is sohigh that it cannot be directly subjected to a shaping step, asolid-liquid separation can be performed before shaping.

Addition of Pore forming Agents The catalyst precursor can be mixed witha pore forming agent including, but not limited to steric acid,polyethylene glycol polymers, carbohydrate polymers, methacrylates, andcellulose polymers. For example, the dried catalyst precursor can bemixed with cellulose containing materials such as methylcellulose,hydroxypropylcellulose, or other cellulose ethers in a ratio of between100:1 and 10:1 (wt. % catalyst precursor to wt. % cellulose) and wateradded until a mixture of extrudable consistency is obtained. Examples ofcommercially available cellulose based pore forming agents include butare not limited to: methocel (available from Dow Chemical Company),avicel (available from FMC Biopolymer), and porocel (available fromPorocel). The extrudable mixture can be extruded and then optionallydried. In one embodiment, the drying can be performed under an inertatmosphere such as nitrogen, argon, or vacuum. In another embodiment,the drying can be performed at elevated temperatures between 70 and 200°C. In yet another embodiment, the drying is performed at 120° C.

Sulfiding Agent Component: The charge-neutral catalyst precursor can besulfided to form an active catalyst. In one embodiment, the sulfidingagent is elemental sulfur by itself In another embodiment, the sulfidingagent is a sulfur-containing compound which under prevailing conditions,is decomposable into hydrogen sulphide. In yet a third embodiment, thesulfiding agent is H₂S by itself or H₂S in H₂.

In one embodiment, the sulfiding agent is selected from the group ofammonium sulfide, ammonium polysulfide ([(NH₄)₂S_(x)), ammoniumthiosulfate ((NH₄)₂S₂O₃), sodium thiosulfate Na₂S₂O₃), thiourea CSN₂H₄,carbon disulfide, dimethyl disulfide (DMDS), dimethyl sulfide (DMS),dibutyl polysulfide (DBPS), mercaptanes, tertiarybutyl polysulfide(PSTB), tertiarynonyl polysulfide (PSTN), and the like. In anotherembodiment, the sulfiding agent is selected from alkali- and/or alkalineearth metal sulfides, alkali-and/or alkaline earth metal hydrogensulfides, and mixtures thereof The use of sulfiding agents containingalkali- and/or alkaline earth metals can require an additionalseparation process step to remove the alkali- and/or alkaline earthmetals from the spent catalyst.

In one embodiment, the sulfiding agent is ammonium sulfide in aqueoussolution, which aqueous ammonium sulfide solution can be synthesizedfrom hydrogen sulfide and ammonia refinery off-gases. This synthesizedammonium sulfide is readily soluble in water and can easily be stored inaqueous solution in tanks prior to use. In one embodiment wherein thesulfidation is with an aqueous ammonium sulfide solution, and also inthe presence of at least a sulfur additive selected from the group ofthiodazoles, thio acids, thio amides, thiocyanates, thio esters, thiophenols, thiosemicarbazides, thioureas, mercapto alcohols, and mixturesthereof.

In one embodiment, hydrocarbon feedstock is used as a sulfur source forperforming the sulfidation of the catalyst precursor. Sulfidation of thecatalyst precursor by a hydrocarbon feedstock can be performed in one ormore hydrotreating reactors during hydrotreatment.

In one embodiment, the sulfiding agent is present in an amount in excessof the stoichiometric amount required to form the sulfided catalyst fromthe catalyst precursor. In another embodiment, the amount of sulfidingagent represents a sulphur to Group VIB metal mole ratio of at least 3to 1 to produce a sulfided catalyst from the catalyst precursor. In athird embodiment, the total amount of sulfur-containing compound isgenerally selected to correspond to any of about 50-300%, 70-200%, and80-150%, of the stoichiometric sulfur quantity necessary to convert themetals into for example, CO₉S₈, MoS₂, WS₂, Ni₃S₂, etc.

Sulfiding Step: Sulfiding (sometimes referred to as “presulfiding”) ofthe catalyst precursor to form the catalyst can be performed prior tointroduction of the catalyst into a hydrotreating reactor (thus ex-situsulfiding). In another embodiment, the sulfiding is in-situ. In oneembodiment with the sulfiding process being done ex-situ, the formationof undesirable compounds in the hydrotreating unit is prevented. In oneembodiment, the catalyst precursor is converted into an active catalystupon contact with the sulfiding agent at a temperature ranging from 70°C. to 500° C., from 10 minutes to 15 days, and under a H₂-containing gaspressure. If the sulfidation temperature is below the boiling point ofthe sulfiding agent, such as 60-70° C. in the case of ammonium sulphidesolution, the process is generally carried out at atmospheric pressure.Above the boiling temperature of the sulfiding agent/optionalcomponents, the reaction is generally carried out at an increasedpressure.

In one embodiment, the sulfiding can be carried out in the gaseous phasewith hydrogen and a sulfur-containing compound which is decomposableinto H₂S. Examples include mercaptanes, CS₂, thiophenes, DMS, DMDS andsuitable S-containing refinery outlet gasses. The use of H₂S alone issufficient. The contacting between the catalyst precursor in gaseousphase with hydrogen and a sulfur-containing compound can be done in onestep at a temperature between 125° C. to 450° C. (257° F. to 842° F.) inone embodiment, and between 225° C. to 400° C. (437° F. to 752° F.) inanother embodiment. In one embodiment, the sulfidation is carried outover a period of time with the temperature being increased inincrements, e.g., from 0.5 to 4° C. (0.9 to 7.2° F.) per min. and heldover a period of time, e.g., from 1 to 12 hours, until completion.

As used herein, completion of the sulfidation process means that atleast 95% of stoichiometric sulfur quantity necessary to convert themetals into for example, CO₉S₈, MoS₂, WS₂, Ni₃S₂, etc., has been usedup.

In another embodiment of sulfidation in the gaseous phase, thesulfidation is done in two or more steps, with the first step being at alower temperature than the subsequent step(s). For example, the firststep is at about 100 to 250° C. (212° F. to 482° F.), preferably about125 to 225° C. (257° F. to 437° F.). After a short period of time, e.g.,from ½ to 2 hours (temperature kept at a plateau). The second step canbe carried out at about 225 to 450° C. (437° F. to 842° F.), andpreferably about 250 to 400° C. (482° F. to 752° F.). The total pressureduring the sulfidation step can be between atmospheric and about 10 bar(1 MPa). The gaseous mixture of H₂ and sulfur containing compound can bethe same or different in the steps. The sulfidation in the gaseous phasecan be done in any suitable manner, including a fixed bed process and amoving bed process (in which the catalyst moves relative to the reactor,e.g., ebullated process and rotary furnace).

In one embodiment, the sulfidation is carried out in the liquid phase.At first, the catalyst precursor is brought in contact with an organicliquid in an amount in the range of 20-500% of the catalyst precursorpore volume. The contacting with the organic liquid can be at atemperature ranging from ambient to 250° C. (482° F.). After theincorporation of an organic liquid, the catalyst precursor is broughtinto contact with hydrogen and a sulfur-containing compound.

In one embodiment, the organic liquid has a boiling range of about100-550° C. (212-1022° F.). In another embodiment, the organic liquid isa petroleum fraction such as heavy oils, lubricating oil fractions likemineral lube oil, atmospheric gas oils, vacuum gas oils, straight rungas oils, white spirit, middle distillates like diesel, jet fuel andheating oil, naphthas, and gasoline. In one embodiment, the organicliquid contains less than 10 wt. % sulfur, and preferably less than 5wt. %.

In one embodiment, the sulfidation (or “start-up”) in the liquid phaseis done as a “quick” process, with the sulfidation taking place over aperiod of less than 72 hours and with the ramp-up in temperature rangesfrom 0.5 to 4° C. (0.9 to 7.2° F.) per min. In a second embodiment, thequick start-up takes less than 48 hours. In a third embodiment, lessthan 24 hours.

In the quick sulfidation, the contacting between the catalyst precursorin organic liquid with hydrogen and a sulfur-containing compound can bedone in one step at a temperature between 150 to 450° C. in oneembodiment, and between 225° C. to 400° C. in another embodiment. In yetanother embodiment of the quick sulfidation, the sulfidation is done intwo or more steps, with the first step being at a lower temperature thanthe subsequent step(s). For example, the first step is at about 100 to250° C. (212° F. to 482° F.), or from 125 to 225° C. (257° F. to 437°F.). After a short period of time, e.g., from ½ to 2 hours (temperaturekept at a plateau), then the temperature is ramped up for the secondstep, e.g., from 250 to 450° C. (482° F. to 842° F.), and preferablyfrom 225 to 400° C. (437° F. to 7520° F.). The temperature is maintainedfrom 1 to 36 hours, after which time sulfidation is complete.

In yet another embodiment, the sulfidation in the liquid phase is doneas a “slow” process, with the sulfidation taking place over a period oftime from four (4) days up to three weeks, i.e., at least 96 hours. Inthis slow process, the contacting between the catalyst precursor inorganic liquid with hydrogen and a sulfur-containing compound is done intwo or more steps, with the first step being at a lower temperature thanthe subsequent step(s) and with the temperature being increased slowlyin increments, e.g., per hour instead of per minute as in the quickstart up. The gaseous mixture of H₂ and sulfur containing compound canbe the same or different in the steps. In one embodiment, the first stepis at about 100 to 375° C. (212° F. to 707° F.), preferably about 125 to350° C. (257° F. to 662° F.), with a temperature ramp rate from 0.25 to4° C. (0.45 to 7.2° F.) per hour. After the first step, temperature isheld constant for a period of time from 2 to 24 hours, then ramped upfor the second step at a rate from 5 to 20° C. (9 to 36° F.) per hour.In one embodiment, the second step is carried out at about 200 to 450°C. (392° F. to 842° F.), and preferably about 225 to 400° C. (437° F. to752° F.).

In one embodiment, the sulfiding is done with elemental sulfur, whereinthe sulfur is incorporated into the pores of the catalyst precursors. Inthis process, elemental sulfur is mixed with the catalyst precursor inan amount from 2 to 15 wt. % of the catalyst precursor weight, at atemperature below the melting point of sulfur. In one embodiment, themixing is at 180 to 210° F. (820 to 99° C.). Sequentially orsimultaneously with the mixing of precursor and elemental sulfur, themixture is brought into contact with a high boiling organic liquid. Themixture is then heated to a temperature in the range of 250 to 390° F.(121° to 199° C.) in the presence of nitrogen, producing H₂S and metalsulfides. In one embodiment, the organic liquid is selected from thegroup consisting of olefins, gasoline, white spirit, diesel, gas oils,mineral lube oils, and white oils.

In one embodiment, it is found that catalysts sulfided from embodimentsof the catalyst precursors surprisingly give about the same 700° F.+conversion rate whether sulfided via the gaseous phase, or in the liquidphase as a “quick” process. In one embodiment, it is found that the 700°F.+ conversion increases at least 25% with the use of catalysts sulfidedin the liquid phase and via the “slow” process. In yet anotherembodiment, the 700° F.+ conversion doubles with a catalyst sulfided viathe slow process.

Use of The Catalyst The multi-metallic catalyst prepared from thecatalyst precursor composition can be used in virtually allhydroprocessing processes to treat a plurality of feeds underwide-ranging reaction conditions such as temperatures of from 200 to450° C., hydrogen pressures of from 15 to 300 bar, liquid hourly spacevelocities of from 0.05 to 10 h⁻¹ and hydrogen treat gas rates of from35.6 to 2670 m³/m³ (200 to 15000 SCF/B− or “Standard Cubic Feet perBarrel” of hydrocarbon compound feed to the reactor).

The hydroprocessing process can be practiced in one or more reactionzones, and can be practiced in either countercurrent flow or co-currentflow mode. By countercurrent flow mode is meant a process wherein thefeed stream flows countercurrent to the flow of hydrogen-containingtreat gas. The hydroprocessing also includes slurry and ebullating bedhydrotreating processes for the removal of sulfur and nitrogen compoundsand the hydrogenation of aromatic molecules present in light fossilfuels such as petroleum mid-distillates, e.g., hydrotreating a heavy oilemploying a circulating slurry catalyst precursor.

The hydroprocessing process can be single staged or multiple-staged. Inone embodiment, the process is a two stage system wherein the first andsecond stages employ different catalysts, and wherein at least one ofthe catalysts used in the system is prepared from the catalyst precursorcomposition of the invention.

The feeds for use in hydroprocessing processes using the catalystprepared from the catalyst precursor can include petroleum and chemicalfeedstocks such as olefins, reduced crudes, hydrocrackates, raffinates,hydrotreated oils, atmospheric and vacuum gas oils, coker gas oils,atmospheric and vacuum resids, deasphalted oils, dewaxed oils, slackwaxes, Fischer-Tropsch waxes and mixtures thereof. Specific examplesrange from the relatively light distillate fractions up to high boilingstocks such as whole crude petroleum, reduced crudes, vacuum towerresidua, propane deasphalted residua, brightstock, cycle oils, FCC towerbottoms, gas oils including coker gas oils and vacuum gas oils,deasphalted residua and other heavy oils. In one embodiment, thefeedstock is a C₁₀₊ feedstock. In another embodiment, the feedstock isselected from distillate stocks, such as gas oils, kerosenes, jet fuels,lubricating oil stocks boiling above 230° C., heating oils, hydrotreatedoil stock, furfural-extracted lubricating oil stock and other distillatefractions whose pour point and viscosity properties need to bemaintained within certain specification limits.

In one embodiment, the feedstocks contain a substantial amount ofnitrogen, e.g. at least 10 wppm nitrogen, in the form of organicnitrogen compounds. The feeds can also have a significant sulfurcontent, ranging from about 0.1 wt. % to 3 wt. %, or higher

The hydrotreating processes using catalysts prepared from the catalystprecursor can be suitable for making lubricating oil base stocks meetingGroup II or Group III base oil requirements. In one embodiment, thecatalyst precursor is used in preparing a catalyst for use in ahydroprocessing process producing white oils. White mineral oils, calledwhite oils, are colorless, transparent, oily liquids obtained by therefining of crude petroleum feedstocks.

Catalysts prepared from the catalyst precursor can be applied in anyreactor type. In one embodiment, the catalyst is applied to a fixed bedreactor. In another embodiment, two or more reactors containing thecatalyst can be used in series. The catalyst can be used as a slurry inan unsupported form or in a supported matrix such as alumina or silica.

In one embodiment, the multi-metallic catalyst prepared from thecatalyst precursor is used in a fixed bed hydroprocessing reactor byitself In another embodiment, the multi-metallic catalyst is inconjunction with at least a different catalyst in a fixed bed reactor,wherein the catalysts are packed in a stacked-bed manner. In oneembodiment, the multi-metallic catalyst is employed in a layered/gradedsystem, with a first layer catalyst having larger pore size, and thesecond layer being an embodiment of the multi-metallic catalyst of theinvention.

In one embodiment wherein the multi-metallic catalyst prepared from thecatalyst precursor is used in a layered bed system, the multi-metalliccatalyst comprises at least 10 vol. % of the total catalyst. In a secondembodiment, the multi-metallic catalyst comprises at least 25 vol. % ofthe catalyst system. In a third embodiment, the multi-metallic catalystcomprises at least 35 vol. % of the layered catalyst system. In a fourthembodiment, the multi-metallic catalyst comprises at least 50 vol. % ofa layered bed system. In a fifth embodiment, the multi-metallic catalystcomprises 80 vol. % of a layered bed system.

In one embodiment, the multi-metallic catalyst prepared from thecatalyst precursor is characterized as being less susceptible to foulingcompared to the catalysts of the prior art when employed inhydrogenation processes, i.e., having a lower fouling rate.

In one embodiment wherein the multi-metallic prepared from the catalystprecursor is employed as the sole catalyst in a reactor system, themulti-metallic catalyst has a fouling rate of less than 8° F. (4.4° C.)per 1000 hour, i.e., that is, the catalytic reactor temperature needs tobe increased no more than 8° F. per 1000 hour in order to maintain atarget nitrogen level of 20 ppm in the upgraded products of ahydrodenitrogenation (HDN) process. As described in the definitionsection for fouling rate, the feed in this HDN process is vacuum gas oil(VGO) having properties of 4.6 CSt viscosity at 100° C., 0.928 g/ccdensity, 178-495° C. boiling range, and 1.66 hydrogen to carbon atomicratio. The process condition includes a temperature of 370-425° C., 10MPa pressure, 1.0 h⁻¹ LHSV, and hydrogen flow rate of 5000 scfb. The HDNtarget is a nitrogen level of 20 ppm in the upgraded products.

In yet another embodiment where the multi-metallic catalyst is the solecatalyst, the multi-metallic catalyst has a fouling rate of less than 5°F. (2.8° C.) per 1000 hour. In a third embodiment, the fouling rate isless than 2.5° F. (1.9° C.) per 1000 hour.

In yet another embodiment when employed in a fixed bed hydroprocessingreactor having three layers of three different catalysts and with themulti-metallic catalyst comprising between 10-80 vol., this catalystsystem has a fouling rate of less than 30° F. (16.7° C.) per 1000 hourat a target N concentration of 20 wtppm in the upgraded product using aVGO feed as described above (also see Table 3). In a second embodiment,the fouling rate is less than 26° F. (14.4° C.) per 1000 hour for asystem wherein the catalyst comprises at least 25 vol. % of the layeredcatalyst system. In a third embodiment, a catalyst system comprising atleast 35 vol. % of the multi-metallic catalyst has a fouling rate ofless than 19° F. (10.6° C.) per 1000 hour at the same N target (20 wtppmN in the whole liquid product). In a fourth embodiment, a catalystsystem comprising at least 50 vol. % of the multi-metallic catalyst hasa fouling rate of less than 10° F. (5.6° C.) per 1000 hour at the same Ntarget (20 wtppm N in the whole liquid product).

In one embodiment, the multi-metallic catalyst based on the precursor ofthe invention can be used for hydroprocessing under low hydrogen partialpressure, e.g., a hydrocracking process having a hydrogen partialpressure of lower than 600 psig. This is surprising in view of the priorart teachings concerning the adverse effects of low hydrogen partialpressures on catalyst activity. In one embodiment, the multi-metalliccatalyst is used for hydroprocessing under a hydrogen partial pressureof less than 500 psig. In a second embodiment, the multi-metalliccatalyst is for use under a hydrogen partial pressure between 400 to 600psig. In a third embodiment, the hydrogen partial pressure is between400 and 500 psig. The applicability of low pressures employingembodiments of the multi-metallic catalyst is particularly preferredsince it results in large savings in construction and operating costs.

In one embodiment of a hydroconversion process under a hydrogen partialpressure of about 400 psig, the multi-metallic catalyst gives a 700° F.+conversion of at least 50% of the 700° F.+ conversion obtained at ahydrogen partial pressure of about 600 psig. In a second embodiment,700° F.+ conversion rate at a hydrogen partial pressure of about 400psig or lower is at least 75% the 700° F.+ conversion obtained at ahydrogen partial pressure of about 600 psig or higher. In a thirdembodiment, the 700° F.+ conversion rate at a hydrogen partial pressureof about 400 psig or lower is at least 80% the 700° F.+ conversionobtained at a hydrogen partial pressure of about 600 psig or higher.

In one embodiment of a hydroconversion process under a hydrogen partialpressure in the range of 450 to 500 psig, the multi-metallic catalystbased on the precursor of the invention removes at least 70% of thenitrogen removed under comparable conditions, but at hydrogen partialpressure of greater than 2000 psig.

EXAMPLES

The following illustrative examples are intended to be non-limiting.

Example 1

Ni—Mo—W-maleate catalyst precursor. A catalyst precursor of the formula(NH₄){[Ni_(2.6)(OH)_(2.08)(C₄H₂O₄ ²⁻)_(0.06)](Mo_(0.35)W_(0.65)O₄)₂} wasprepared as follows: 52.96 g of ammonium heptamolybdate(NH₄)₆Mo₇O₂₄.4H₂O was dissolved in 2.4 L of deionized water at roomtemperature. The pH of the resulting solution was within the range of5-6. 73.98 g of ammonium metatungstate powder was then added to theabove solution and stirred at room temperature until completelydissolved. 90 ml of concentrated (NH₄)OH was added to the solution withconstant stirring. The resulting molybdate/tungstate solution wasstirred for 10 minutes and the pH monitored. The solution had a pH inthe range of 9-10. A second solution was prepared containing 174.65 g ofNi(NO₃)₂.6H₂O dissolved in 150 ml of deionized water and heated to 90°C. The hot nickel solution was then slowly added over 1 hr to themolybdate/tungstate solution. The resulting mixture was heated to 91° C.and stirring continued for 30 minutes. The pH of the solution was in therange of 5-6. A blue-green precipitate formed and the precipitate wascollected by filtration. The precipitate was dispersed into a solutionof 10.54 g of maleic acid dissolved in 1.8 L of DI water and heated to70° C. The resulting slurry was stirred for 30 min. at 70° C., filtered,and the collected precipitate vacuum dried at room temperatureovernight. The material was then further dried at 120° C. for 12 hr. Theresulting material has a typical XRD pattern with a broad peak at 2.5Å,denoting an amorphous Ni—OH containing material. The BET Surface area ofthe resulting material was 101 m²/g, the average pore volume was around0.12-0.14 cc/g, and the average pore size was around 5 nm.

Example 2

Co—Mo—W-maleate catalyst precursor. A catalyst precursor of the formula(NH₄){[Co_(3.0)(OH)_(3.0-c)(C₄H₂O₄ ²⁻)_(c/2)](Mo_(0.34)W_(0.66)O₄)₂} wasprepared as follows: 2.0 g of maleic acid was dissolved in 800 g ofdeionized water at room temperature. The pH of the resulting solutionwas within the range of 2-3. 17.65 g of ammonium heptamolybdate(NH₄)₆Mo₇O₂₄.4H₂O powder was dissolved in the above solution, followedby addition of 24.67 g of ammonium metatungstate(NH₄)₆H₂W₁₂O₄₀.xH₂O(>66.5% W). The pH of the resulting solution waswithin the range of 4-5. 30ml of concentrated (NH₄)OH was added to thesolution with constant stirring. The resulting molybdate/tungstatesolution was stirred for 10 minutes and the pH monitored. The solutionhad a pH in the range of 9-10 at room temperature and was heated to 90°C. A second solution was prepared containing 58.28 g of cobalt nitratedissolved in 50 g of deionized water. The hot cobalt solution was thenslowly added over 25 min to the hot molybdate/tungstate solution. Theresulting mixture was continuously stirred at 90° C. for 1 hour. The pHof the solution was around 6. A dark purplish brown precipitate thatformed in the process was collected by filtration. The precipitate wasdispersed into 250 g of DI water at 70° C. The resulting slurry wasstirred for 30 min., filtered, and the collected precipitate vacuumdried at room temperature overnight. The material was then further driedat 120° C. for 12 hr.

Example 3

Co—Mo—W catalyst precursor. A catalyst precursor of the formula(NH₄)⁺{[Co_(3.31)(OH)_(3.62)](Mo_(0.3)W_(0.7)O₄)₂} was preparedaccording to the following procedure: 17.65 g of ammonium heptamolybdate(NH₄)₆Mo₇O₂₄.4H₂O powder was dissolved in 800.00 g of deionized water atroom temperature followed by addition of 24.66 g of ammoniummetatungstate (NH₄)₆H₂W₁₂O₄₀.xH₂O (>66.5% W). The pH of the resultingsolution was within the range of 5.2-5.4. A second solution was preparedcontaining 58.26 g of cobalt nitrate hexahydrate dissolved in 50.0 g ofdeionized water. The pH of the resulting solution was within the rangeof 1-2. 30 ml of concentrated (NH₄)OH was added to the solution withconstant stirring. Initially moss green in color precipitate was formedlater turning into a 2 layer mixture with a greenish suspension at thebottom and a top brownish layer. The cobalt containing mixture was thenslowly added over 25 min to the molybdate/tungstate solution at roomtemperature. The pH of the resulting solution was within the range of8-8.5. The mixture was heated to 80° C. and continuously stirred for 1hour. A purplish grey suspension was filtered while hot. The precipitatewas dispersed into 2.5 L of DI water at 70° C. The resulting slurry wasstirred for 30 min (pH˜7.6), filtered, and the collected precipitatevacuum dried at room temperature overnight. The material was thenfurther dried at 120° C. for 12 hr.

Example 4

Extrusion process. In this example, 40 g of dried catalyst precursorprepared as per examples 1-3 was mixed with 0.8 g of methocel, (acommercially available methylcellulose and hydroxypropyl methylcellulosepolymer from Dow Chemical Company), and approximately 7 g of DI waterwas added. Another 7 g of water was slowly added until the mixture wasof an extrudable consistency. The mixture was then extruded and driedunder N₂ at 120° C. prior to sulfiding.

Example 5

Sulfidation DMDS liquid phase. The catalyst precursors of Examples 1-3were placed in a tubular reactor. The temperature was raised from roomtemperature to 250° F. at a rate of 100° F./hr under N_(2(g)) at 8ft³/hr. The reaction was continued for 1 hour after which time the N₂was switched off and replaced with H₂ at 8 ft³/hr and 200 psig for 1hour. Light VGO oil (end point below 950° F.) was pumped over thecatalyst precursor at 250° F. at a rate of 130 cc/hr (1 LHSV) while thehydrogen gas rate at 8 cubic feet an hour was maintained. The catalystprecursor was then heated to 430° F. at a rate of 25° F./hr and dimethyldisulfide (DMDS) was added to the light VGO at a rate of 4 cc/hr forapproximately 4 hr. The catalyst precursor was then heated to 600° F.,and the rate of DMDS addition increased to 8 cc/hr. The temperature wasmaintained at 600° F. for 2 hours after which time sulfidation wascomplete.

Example 6

Sulfidation with DMDS gas phase. Catalyst precursors of Examples 1-3extruded as per example 4 were placed in a tubular reactor. Thetemperature was raised to 450° F. at a rate of 100° F./hr under N_(2(g))at 8 ft³/hr. The reaction was continued for 1 hour after which time theN₂ was switched off and replaced with H₂ at 8 ft³/hr and 100 psig for 1hour. The H₂ pressure was then increased to 300 psig and maintained forless than 1 hr. after which time dimethyl disulfide (DMDS) was added ata rate of 4 cc/hour and then reaction allowed to proceed for 4 hr. Thecatalyst precursor was then heated to 600° F. and the rate of DMDSaddition increased to 8 cc/hr. The temperature was maintained at 600° F.for 2 hours after which time sulfidation was complete.

Example 7

Catalyst/Catalyst Precursor Comparison. In this examples, variouscatalysts/catalyst precursors were evaluated and compared, includingconventional catalysts (Ni—Mo on alumina, Co—Mo—W and Ni—Mo—Wunsupported catalysts) and various embodiments of the sulfided catalystprecursors (Co—Mo—W-maleate example 2, Co—Mo—W of example 3, andNi—Mo—W-maleate example 1). The evaluation included hydrocracking, HDS,and HDN activity using a vacuum gas oil (VGO) feedstock with a boilingpoint above 700° F., a sulfur content of 31135 ppm, a nitrogen contentof 31230 ppm, and other properties as presented in Table 1. The reactorconditions were at a pressure of 2300 psi, an H₂ gas rate of 5000 SCFB,and an LHSV of 0.75.

Ni/Mo/alumina is a conventional supported catalyst. Ni/Mo/W is anunsupported catalyst along the line of the catalyst referenced in U.S.Pat. No. 6,712,955 and U.S. Pat. No. 6,299,760. Ni/Mo/W/maleate,Co/Mo/W, and Co/Mo/W/maleate, and are catalyst precursors made perexamples 1, 2, and 3 respectively, and sulfided as per example 6.Results of the evaluation are presented in Table 2.

FIG. 1 is a powder X-ray diffraction pattern (“XRD”) of the comparativeunsupported catalyst precursor Ni/Mo/W. FIG. 2 is a XRD of the catalystprecursor based on the Ni/Mo/W/maleate of Example 1. FIG. 3 is a XRD ofa second embodiment of the invention, a catalyst based on theCo/Mo/W/maleate precursor of example 2. FIG. 4 is a XRD of thecomparative catalyst precursor Co/Mo/W of Example 3. In the XRDsfigures, the catalyst samples were generally washed in DI water for10-15 minutes to wash off any unreactive salts prior to the XRD.

TABLE 1 Properties VGO Feedstock API Gravity 20.0 N, ppm 1100 S, wt %2.72 Carbon, wt % 85.6 22 compounds Aromatics, vol % 35.0 Naphthenes,vol % 27.8 Paraffins, vol % 13.5 Sulfur compounds, vol % 23.7 Simdist,wt % 0.5/5 640/689   10/30 717/800   50/ 866  70/90 930/1013  95/99163/1168

TABLE 2 Ni/Mo/ Ni/Mo/W/ Co/Mo/W/ Feedstock alumina Ni/Mo/W maleateCo/Mo/W maleate 700 F.+ conversion 34.1 30.0 30.0 20.7 31.1 (wt-%/wt-%)Temperature (° F.) 725 700 690 700 700 No Loss yields, Wt % C4 minus 0.01.1 0.9 0.5 0.6 1.0 C5-180° F. 0.0 1.0 0.7 1.6 0.6 0.9 180-700° F. 6.536.2 32.77 32.05 24.35 33.43 700° F.+ 93.5 62.2 66.0 64.1 74.8 65.1Sulfur, ppm 2.7E+04 7.5 8.3 8 281.4 126.8 Nitrogen, ppm 1.2E+03 <0.251.2 1 17.4 4.0

As shown in the table, when the Group VIII metal was nickel, theaddition of an organic oxygen containing ligand to the synthesis of thecatalyst precursor improved the catalytic activity by lowering the 30%conversion temperature from 725 (conventional Ni—Mo-alumina) and 700(Ni—Mo—W prior art) to 690 (Ni—Mo—W-maleate). When the group VIII metalwas cobalt, the same trend was evident with increased activity when anorganic oxygen containing ligand (maleate) was added to the catalystprecursor preparation.

Example 8

HDN systems employing catalyst: Performance of a catalyst employing anembodiment of the catalyst precursor was evaluated in ahydrodenitrogenation (HDN) system.

Comparative Catalyst System I employs two layers. The first layercomprises 20 vol. % of Catalyst A, a commercially availablehigh-activity catalyst for hydrocracking pretreat applications fromChevron Lummus Global of San Ramon, Calif. of a pore size in the rangeof from 80 to 100 angstroms (Å). The second layer comprises 80 vol. % ofanother commercially available high-activity catalyst for hydrocrackingpretreat applications, Catalyst B, also from Chevron Lummus Global, witha smaller pore size in the range of from 70 to 90 Å.

Catalyst System II employs an embodiment of a multi-metallic catalystusing the catalyst precursor in a layered system. The top layercomprises 20 vol. % of Catalyst A, the middle layer comprises 55 vol. %of Catalyst B, and the bottom layer comprises 25 vol. % of a catalystprepared from the catalyst precursor of Example 1.

The catalyst precursors in this example were sulfided using a liquidphase sulfiding procedure, i.e., extended contacting of the catalystwith the sulfiding feed (e.g., dimethyl disulfide in diesel or light VGOas in Example 5) at about 175-250° F., followed by slow ramping ofreactor temperature to 550-700° F.

In both systems, after sulfiding, the system total pressure wasincreased to 1500 psig and changed over to a straight run light VGOfeed. The reactor temperature was increased to 620° F. and heldrelatively steady for three days. After that, the reactor temperaturewas increased to 700-780° F., and the system was run at 1500 psig totalpressure (1400 psia H₂ at the reactor inlet); 5000 SCF/B once through H₂feed, and 1.0 h⁻¹ LHSV. A petroleum feedstock having properties aslisted in Table 3 was processed through both catalyst systems for ahydrotreating (or HDT) target of 20 wtppm N in the whole liquid product(“WLP”).

TABLE 3 Feedstock used for fouling rate testing Properties Feedstock APIGravity 20.9 N, ppm 2600 S, wt % 0.82 Carbon, wt % 86.69 Hydrogen (NMR),wt % 12.00 22 compounds Aromatics, vol % 42.4 Naphthenes, vol % 38.8Paraffins, vol % 9.8 Sulfur compounds, vol % 9.0 Oxygen by NAA, wt %0.30 Simdist, wt % 0.5/5 353/533  10/30 579/673  50/ 747  70/90 816/871 95/99 890/923

Table 4 lists the yields and product properties of the HDN runscomparing the two systems after 480 hours on stream. The results showedthat the system II employing the catalyst made with an embodiment of thecatalyst precursor demonstrates at least 20° F. more active in HDN(hydrodenitrogenation) activity than the catalyst system I with theprior art. For example, Catalyst System II gave 17.7 ppm nitrogen in thestripper bottoms product with a C.A.T. of 731° F. at 480 hours, whereinComparative Catalyst System I gave 17.5 ppm nitrogen for a C.A.T. of751° F. at 504 hours.

FIG. 5 further illustrates/compares the fouling rate of the two catalystsystems, System I with the prior art catalysts, and System II comprisinga catalyst made from an embodiment of the catalyst precursor. As shown,Comparative Catalyst System I has a fouling rate of 32° F. per 1000hours as opposed to Catalyst System II with a fouling rate of 26° F. per1000 hours. At the end of the run, the C.A.T. of both systems had to beraised to get the same desired HDN conversion rate, i.e., less than 20wtppm N in the WLP. For System II, the C.A.T. was raised to 741° F. at888 hours vs. 766° F. at 1008 hours for System I.

Example 9

HDN systems employing catalyst: Performance of a catalyst employing anembodiment of the catalyst precursor was evaluated in ahydrodenitrogenation (HDN) system.

Comparative Catalyst System I employs two layers. The first layercomprises 20 vol. % of Catalyst A, a commercially availablehigh-activity catalyst for hydrocracking pretreat applications fromChevron Lummus Global of San Ramon, Calif. of a pore size in the rangeof from 80 to 100 angstroms (Å). The second layer comprises 80 vol. % ofanother commercially available high-activity catalyst for hydrocrackingpretreat applications, Catalyst B, also from Chevron Lummus Global, witha smaller pore size in the range of from 70 to 90 Å.

Catalyst System II employs an embodiment of a multi-metallic catalystusing the catalyst precursor in a layered system. The top layercomprises 20 vol. % of Catalyst A, the middle layer comprises 55 vol. %of Catalyst B, and the bottom layer comprises 25 vol. % of a catalystprepared from the catalyst precursor of Example 1.

The catalyst precursors in this example were sulfided using a liquidphase sulfiding procedure, i.e., extended contacting of the catalystwith the sulfiding feed (e.g., dimethyl disulfide in diesel or light VGOas in example 5) at about 175-250° F., followed by slow ramping ofreactor temperature to 550-700° F.

In both systems, after sulfiding, the system total pressure wasincreased to 1500 psig and changed over to a straight run light VGOfeed. The reactor temperature was increased to 620° F. and heldrelatively steady for three days. After that, the reactor temperaturewas increased to 700-780° F., and the system was run at 1500 psig totalpressure (1400 psig H₂ at the reactor inlet); 5000 SCF/B once through H₂feed, and 1.0 h⁻¹ LHSV. A petroleum feedstock having properties aslisted in Table 3 was processed through both catalyst systems for ahydrotreating (or HDT) target of 20 wtppm N in the whole liquid product(“WLP”).

Table 4 lists the yields and product properties of the HDN runscomparing the two systems after 480 hours on stream. The results showedthat the system II employing the catalyst made with an embodiment of thecatalyst precursor demonstrates at least 20° F. more active in HDN(hydrodenitrogenation) activity than the catalyst system I with theprior art. For example, Catalyst System II gave 17.7 ppm nitrogen in thestripper bottoms product with a C.A.T. of 731° F. at 480 hours, whereinComparative Catalyst System I gave 17.5 ppm nitrogen for a C.A.T. of751° F. at 504 hours.

FIG. 5 further illustrates/compares the fouling rate of the two catalystsystems, System I with the prior art catalysts, and System II comprisinga catalyst made from an embodiment of the catalyst precursor. As shown,Comparative Catalyst System I has a fouling rate of 32° F. per 1000hours as opposed to Catalyst System II with a fouling rate of 26° F. per1000 hours. At the end of the run, the C.A.T. of both systems had to beraised to get the same desired HDN conversion rate, i.e., 20 wtppm N inthe WLP. For System II, the C.A.T. was raised to 741° F. at 888 hoursvs. 766° F. at 1008 hours for System I.

Example 10

Sulfidation—Slow Sulfidation—DMDS liquid phase. The catalyst precursorsof Example 1 (Ni—Mo—W-maleate catalyst precursor) was placed in atubular reactor. The temperature was raised from room temperature to250° F. at a rate of 100° F./hr under N₂ gas at 8 ft³/hr to dry out thecatalyst precursors. After about 1 hour, at which time the N₂ wasswitched off and replaced with H₂ at 8 ft³/hr and 200 psig for 1 hour.Diesel was pumped over the catalyst precursor at 250° F. at a rate of130 cc/hr (1 LHSV) while the hydrogen gas rate at 8 cubic feet an hourwas maintained. DMDS was added at a rate of 0.4 cc/hr for approximately40 hours, then increased to 0.8 cc/hr, while the catalyst precursor wasslowly heated to 600° F. at a rate of 1.88° F./hr. After reaching 600°F., the catalyst precursor stayed soaked in diesel/DMDS liquid phase for12 hours, then heated up to 700° F. at a rate of 25° F./hr.

Example 11

Evaluation of Catalysts by Different Sulfidation Processes: This testwas similar to Example 7 including evaluations for hydrocracking, HDS,and HDN activity using a vacuum gas oil (VGO) feedstock with propertiesin Table 3, and reactor conditions at a pressure of 2300 psi, an H₂ gasrate of 5000 SCFB, and an LHSV of 0.75. Performance of the catalystsulfided in Example 9 (“slow” sulfidation process) was compared withconventional catalysts (Ni—Mo on alumina, Co—Mo—W and Ni—Mo—Wunsupported catalysts) and embodiments of the catalyst precursorssulfided using a “quick” sulfidation process (Co—Mo—W-maleate of example2 and Ni—Mo—W-maleate of example 1).

The 700° F.+ conversion of the catalyst sulfided in Example 9 (“slow”sulfidation process) was 43 wt-%/wt-% at 695° F., as opposed to the 20to 35 wt-%/wt-% conversion rates obtained from conventional catalysts(Ni—Mo on alumina, Co—Mo—W and Ni—Mo—W unsupported catalysts) andembodiments of the catalyst precursors sulfided using a “quick”sulfidation process (see 700° F.+ conversion results in Table 2).Additionally, the catalyst sulfided in Example 9 yielded a 700° F.+product with 0.5 ppm-wt N, as opposed to the ˜1 ppm-wt N in Example 7.This amounts to a 10-15° F. gain in 700° F.+ conversion and in HDNactivity upon slow sulfidation.

Example 12

Evaluation of Different H2 Partial Pressure: In this example, thecatalyst sulfided in Example 10 (“slow” sulfidation) was evaluated forhydrocracking, HDS, and HDN activity using a vacuum gas oil (VGO)feedstock having the properties shown in Table 5. The catalyst wasevaluated under two different reactor conditions, reactor pressures of400 psi and 600 psi H2 partial presssure respectively, with the same H₂gas rate of 5000 SCFB, and an LHSV of 0.75. At the low pressure of 400psi H2 partial pressure, the 700° F.+ conversion rate was about 15%,half of the 700° F.+ conversion rate of about 30% at 600 psi H2 partialpressure.

TABLE 5 Properties Feedstock API Gravity 20.0 N, ppm 1100 S, wt % 2.72Carbon, wt % 85.6 22 compounds Aromatics, vol % 35.0 Naphthenes, vol %27.8 Paraffins, vol % 13.5 Sulfur compounds, vol % 23.7 Simdist, wt %0.5/5 640/689   10/30 717/800   50/ 866  70/90 930/1013  95/99 163/1168

Example 13

(Zn—Mo—W-maleate catalyst precursor). A catalyst precursor of theformula (NH₄)⁺{[Zn_(2.62)(OH)_(2.16)(C₄H₂O₄²⁻)_(0.04)](Mo_(0.42)W_(0.58)O₄)₂} was prepared as follows: 2.01 g ofmaleic acid was dissolved in 800.06 g of deionized water at roomtemperature. The pH of the resulting solution was within the range of2-3. 17.68 g of ammonium heptamolybdate (NH₄)₆Mo₇O₂₄.4H₂O powder wasdissolved in the above solution, followed by addition of 24.67 g ofammonium metatungstate (NH₄)₆H₂W₁₂O₄₀.xH₂O (>66.5% W). The pH of theresulting solution was within the range of 4-5. 30 ml of concentrated(NH₄)OH was added to the solution with constant stirring. The resultingmolybdate/tungstate solution was stirred for 10 minutes and the pHmonitored. The solution had a pH in the range of 9-10 at roomtemperature and was heated to 90° C. A second solution was preparedcontaining 59.65 g of zinc nitraste hexahydrate dissolved in 50 g ofdeionized water. The hot zinc solution was then slowly added over 25 minto the hot molybdate/tungstate solution. The solution had a pH of about6. The resulting mixture was continuously stirred at 90° C. for 1 hour.A white suspension was filtered while hot. The precipitate was dispersedinto 2.5 L of DI water at 70° C. The resulting slurry was stirred for 30min (pH˜7), filtered, and the collected precipitate vacuum dried at roomtemperature overnight. The material was then further dried at 120° C.for 12 hr. The BET Surface area of the resulting material was 101 m²/g,the average pore volume was around 0.12-0.14 cc/g, and the average poresize was around 5 nm.

The PXRD pattern of the catalyst precursor product is shown in FIG. 6.

Example 14

(another Zn—Mo—W-maleic catalyst precursor). A catalyst of the formula(NH₄)⁺{[Zn_(2.7)(OH)_(2.3)(C₄H₂O₄ ²⁻)_(0.05)](Mo_(0.51)W_(0.49)O₄)₂} wasprepared as follows: 17.65 g of ammonium heptamolybdate(NH₄)₆Mo₇O₂₄.4H₂O powder was dissolved in 800.00 g of deionized water atroom temperature followed by addition of 24.67 g of ammoniummetatungstate (NH₄)₆H₂W₁₂O₄₀.xH₂O(>66.5% W). The pH of the resultingsolution was within the range of 5.2-5.4. 30ml of concentrated (NH₄)OHwas added to the solution with constant stirring. The resultingmolybdate/tungstate solution was stirred for 10 minutes and the pHmonitored. A second solution was prepared containing 59.56 g of zincnitrate hexahydrate dissolved in 50.02 g of deionized water. 2.0 g ofmaleic acid was added to the above solution and dissolved fully. The pHof the resulting solution was within the range of 0-1. The zinc solutionwas then slowly added over 50 min to the molybdate/tungstate solution atroom temperature. The resulting mixture was heated to 90° C. andcontinuously stirred for 1 hour. A white suspension was filtered whilehot. The precipitate was dispersed into 2.5 L of DI water at 70° C. Theresulting slurry was stirred for 30 min (pH˜7), filtered, and thecollected precipitate vacuum dried at room temperature overnight. Thematerial was then further dried at 120° C. for 12 hr.

The PXRD pattern of the resulting catalyst precursor is shown in FIG. 7.

Example 15

Extrusion process. In this example, 40 g of dried catalyst precursorprepared as per Examples 1, 13, and 14 was mixed with 0.8 g of methocel,(a commercially available methylcellulose and hydroxypropylmethylcellulose polymer from Dow Chemical Company), and approximately 7g of DI water was added. Another 7 g of water was slowly added until themixture was of an extrudable consistency. The mixture was then extrudedand dried under N₂ at 120° C. prior to sulfiding.

Example 16

Sulfidation DMDS liquid phase. The catalyst precursors of Examples 1,13, and 14 were placed in a tubular reactor. The temperature was raisedto 250° F. at a rate of 100IF/hr under N2(g) at 8 ft³/hr. The reactionwas continued for 1 hour after which time the N₂ was switched off andreplaced with H₂ at 8 ft³/hr and 200 psig for 1 hour. VGO oil was pumpedover the catalyst precursor at 250° F. at a rate of 130 cc/hr (1 LHSV)while the hydrogen gas rate at 8 cubic feet an hour was maintained. Thecatalyst precursor was then heated to 430° F. at a rate of 25° F./hr andDMDS was added at a rate of 4 cc/hr for approximately 4 hr. The catalystprecursor was then heated to 600° F., and the rate of DMDS additionincreased to 8 cc/hr. The temperature was maintained at 600° F. for 2hours after which time sulfidation was complete.

Example 17

Sulfidation with DMDS gas phase. The catalyst precursors of Examples 1,13, and 14 were placed in a tubular reactor. The temperature was raisedto 450° F. at a rate of 100° F./hr under N2(g) at 8 ft³/hr. The reactionwas continued for 1 hour after which time the N₂ was switched off andreplaced with H₂ at 8 ft³/hr and 100 psig for 1 hour. The H₂ pressurewas then increased to 300 psgi and maintained for less than 1 hr. afterwhich time dimethyl disulfide was added at a rate of 4 cc/hour and thenreaction allowed to proceed for 4 hr. The catalyst precursor was thenheated to 600° F. and the rate of DMDS addition increased to 8 cc/hr.The temperature was maintained at 600° F. for 2 hours after which timesulfidation was complete.

Example 18

Catalyst/Catalyst Precursor Comparison. In this examples, variouscatalysts/catalyst precursors were evaluated and compared, includingconventional catalysts and a comparative catalyst employing the catalystprecursor of the type Ni—Mo—W-maleate (Example 1), a comparativecatalyst without the ligand (Example 14), and a catalyst employing anembodiment of the catalyst precursor of the invention (Zn—Mo—W-maleatein Example 13). The evaluation included hydrocracking, HDS, and HDNactivity using a vacuum gas oil (VGO) feedstock with a boiling pointabove 700° F., a sulfur content of 31135 ppm, and a nitrogen content of31230 ppm. The reactor conditions were at a pressure of 2300 psi, an H₂gas rate of 5000 SCFB, and an LHSV of 0.75.

Ni/Mo/alumina is a conventional supported catalyst Ni—Mo on alumina,Ni/Mo/W is an unsupported catalyst of the type disclosed in U.S. Pat.Nos. 6,712,955 and 6,299,760. Ni—Mo—W-maleate, Zn—Mo—W-maleate, andZn—Mo—W are catalyst precursors made per Examples 1, 13, and 14, thensulfided as per example 17 (sulfidation with DMDS gas phase). Theresults of the evaluation are presented in Table 6.

TABLE 6 Ni/Mo/ Ni/Mo/W/ Zn/Mo/W/ Feedstock alumina Ni/Mo/W maleateZn/Mo/W maleate 700 F.+ conversion 34.1 30.0 30.0 19.2 42.1 (wt-%/wt-%)Temperature (° F.) 725 700 690 700 700 No Loss yields, Wt % C4 minus 0.01.07 0.85 0.48 0.75 1.37 C5-180° F. 0.0 0.96 0.72 1.57 0.52 1.64180-700° F. 6.5 36.2 32.77 32.05 22.88 42.84 700° F.+ 93.5 62.16 66.0364.11 76.21 54.69 Sulfur, ppm 2.7E+04 7.5 8.3 8 1.6E+03 11.63 Nitrogen,ppm 1.2E+03 <0.25 1.2 1 95 0.3

As shown in the table, when the Promoter metal was zinc, the addition ofan organic oxygen containing ligand to the synthesis of the catalystprecursor improved the catalytic activity by lowering the 30% conversiontemperature from 725° F. (conventional Ni—Mo-alumina) and 700° F.(Ni—Mo—W prior art) to 690° F. (Ni—Mo—W-maleate) and approximately 680°F. for an embodiment of the invention, Zn—Mo—W-maleate. Additionally,the 700° F.+ conversion is substantially higher than the 700° F.+conversion rate obtained for other catalysts. The Zn—Mo—W-maleatecatalyst yields a higher activity than any conventional catalystconsisting of group VIII metals combined with group VIB metals.

Example 19

Sn-Mo—W-maleate catalyst precursor: A catalyst precursor of the formula(NH₄)⁺{[Sn_(2.26)(OH)_(1.5)(C₄H₂O₄ ²⁻)_(0.01)](Mo_(0.53)W_(0.47)O₄)₂}was prepared as follows: 2.03 g of maleic acid was dissolved in 600.00 gof deionized water at room temperature. The pH of the resulting solutionwas within the range of 2-3. 17.67 g of ammonium heptamolybdate(NH₄)₆Mo₇O₂₄.4H₂O powder was dissolved in the above solution, followedby addition of 24.66 g of ammonium metatungstate (NH₄)₆H₂W₁₂O₄₀.xH₂O(>66.5% W). The pH of the resulting solution was within the range of4-5. 30 ml (27.06 g) of concentrated (NH₄)OH was added to the solutionwith constant stirring. The resulting molybdate/tungstate solution wasstirred for 10 minutes and the pH monitored. The solution had a pH inthe range of 9-10 at room temperature and was heated to 90° C. A secondsolution was prepared containing 42.99 g of tin sulfate dissolved in 250g of deionized water. 91.0 g of 50% sulfuric acid was added to themixture in order to dissolve tin sulfate. The pH of the resultingsolution was within the range of 1.0 to 1.2. The tin solution was thenslowly added over 40 min to the hot molybdate/tungstate solution. Theresulting mixture solution had a pH of about 2. The pH was adjusted toabout 7 by a slow addition of 43.5 ml of concentrated ammoniumhydroxide. The resulting mixture was continuously stirred at 90° C. for1 hour. A product was filtered while hot. The precipitate was dispersedinto 2.5 L of DI water at 70° C. The resulting slurry was stirred for 30min (pH˜7), filtered, and the collected precipitate vacuum dried at roomtemperature overnight. The material was then further dried at 120° C.for 12 hr.

The PXRD pattern of the resulting catalyst precursor is shown in FIG. 8.

Comparative Example 20

Sn—Mo—W catalyst precursor A catalyst of the formula(NH₄)⁺{[Sn_(2.31)(OH)_(1.62)](Mo_(0.55)W_(0.45)O₄)₂} was prepared asfollows: 17.68 g of ammonium heptamolybdate (NH₄)₆Mo₇O₂₄.4H₂O powder wasdissolved in 600 g of DI water, followed by addition of 24.66 g ofammonium metatungstate (NH₄)₆H₂W₁₂O₄₀.xH₂O (>66.5% W). The pH of theresulting solution was within the range of 5-6. 30 ml (27.1 g) ofconcentrated (NH₄)OH was added to the solution with constant stirring.The resulting molybdate/tungstate solution was stirred for 10 minutesand the pH monitored. The solution had a pH of about 10.1 at roomtemperature and was heated to 90° C. A second solution was preparedcontaining 42.99 g of tin sulfate dissolved in 250 g of deionized water.58.82 g of 50% sulfuric acid was added to the mixture in order todissolve tin sulfate. The pH of the resulting solution was within therange of 1.3 to 1.7. The tin solution was then slowly added over 55 minto the hot molybdate/tungstate solution. The resulting mixture solutionhad a pH of about 2. The pH was adjusted to about 7 by a slow additionof 42.31 g of concentrated ammonium hydroxide. The resulting mixture wascontinuously stirred at 90° C. for 1 hour. A product was filtered whilehot. The precipitate was dispersed into 2.5 L of DI water at 70° C. Theresulting slurry was stirred for 30 min (pH˜7), filtered, and thecollected precipitate vacuum dried at room temperature overnight. Thematerial was then further dried at 120° C. for 12 hr.

The PXRD pattern of the resulting comparative catalyst product based onthe precursor is shown in FIG. 9.

Example 21

Mg—Ni—Mo—W-Al-Si-maleate catalyst precursor: A catalyst precursor wasprepared according to the followings: 1) Add 41.52 g of water glass (27%SiO2, ˜14% NaOH Aldrich) to 70 mL of de-ionized water. Stir for 15min.2) Dissolve 12.69 g of Al(NO3)3×9H2O in 70 mL of DI water, pH=2.5 at18.8C. Adjust the pH to ˜1 with ˜1 drop of conc. HNO3. 3) With intenseagitation slowly add the water glass solution to the aluminum nitratesolution. Adjust the stirring to obtain optimum mixing withoutsplashing. Stir for 0.5 hrs. Keep adjusting pH to below 6 withconcentrated HNO3 to avoid gelation. Adjust the pH of the final mixtureto ˜5.5. 4) Dissolve 52.96 g of AHM (NH4)6Mo7O24*4H2O in 1000 g of DIwater. pH˜5.3 21° C. 5) Add 73.98 g of AMT to the above solution. Mix,till complete dissolution (solution clear). pH˜5.3@20° C. 6) Withintense agitation add the above solution to a mixture in of step 3. 7)Adjust the pH with concentrated ammonium hydroxide solution to ˜9.8.Stir for 10 min. 8) Heat the solution to about 90 C. 9) Dissolved 174.65g of Ni(NO3)2*6 H2O in 150 g of DI water. pH˜3.0 at 21° C. 10) Add 42.26g of Mg(NO3)2×6H2O to the above solution. Mix until it is completelydissolved. Measure the pH. 11) Heat the solution to 90C. 12) Slowly addthe solution from step 11 to a solution from step 8 (˜10 min). Stir for2 hrs. Measure the pH. 13) Filter hot the resulting slurry to a moistfilter cake. 14) Dissolve 10.54 g of maleic acid in 1.8 L of DI water.15) Disperse the moist cake from the step 7 into the maleic acidsolution from the step 8. 16) Heat the resulting slurry with agitationto 70° C. and kept it at this temperature for 30 min. 17) Filter hot theresulting blue-green slurry and dry on the funnel at RT under vacuumovernight. 18) Dry the product at 120° C. oven for 12 hrs.

Example 22

Sulfidation DMDS liquid phase. The catalyst precursors of Examples 1 and21 were placed in a tubular reactor. The temperature was raised to 250°F. at a rate of 100° F./hr under N_(2(g)) at 8 ft³/hr. The reaction wascontinued for 1 hour after which time the N₂ was switched off andreplaced with H₂ at 8 ft³/hr and 200 psig for 1 hour. VGO oil was pumpedover the catalyst precursor at 250° F. at a rate of 130 cc/hr (1 LHSV)while the hydrogen gas rate at 8 cubic feet an hour was maintained. Thecatalyst precursor was then heated to 430° F. at a rate of 25° F./hr andDMDS was added at a rate of 4 cc/hr for approximately 4 hr. The catalystprecursor was then heated to 600° F., and the rate of DMDS additionincreased to 8 cc/hr. The temperature was maintained at 600° F. for 2hours after which time sulfidation was complete.

Example 23

Sulfidation with DMDS gas phase. The catalyst precursors of Examples 1and 21 were placed in a tubular reactor. The temperature was raised to450° F. at a rate of 100° F./hr under N_(2(g)) at 8 ft³/hr. The reactionwas continued for 1 hour after which time the N₂ was switched off andreplaced with H₂ at 8 ft³/hr and 100 psig for 1 hour. The H₂ pressurewas then increased to 300 psgi and maintained for less than 1 hr. afterwhich time dimethyl disulfide was added at a rate of 4 cc/hour and thenreaction allowed to procedd for 4 hr. The catalyst precursor was thenheated to 600° F. and the rate of DMDS addition increased to 8 cc/hr.The temperature was maintained at 600° F. for 2 hours after which timesulfidation was complete.

Example 24

Catalyst/Catalyst Precursor Comparison. In this examples, variouscatalysts/catalyst precursors were evaluated and compared. Theevaluation included hydrocracking, HDS, and HDN activity using a vacuumgas oil (VGO) feedstock with a boiling point above 700° F., a sulfurcontent of 31135 ppm, and a nitrogen content of 31230 ppm. The reactorconditions were at a pressure of 2300 psi, an H₂ gas rate of 5000 SCFB,and an LHSV of 0.75.

Ni/Mo/alumina is a conventional supported catalyst, Ni/Mo/W is anunsupported catalyst along the line of the catalyst referenced in U.S.Pat. No. 6,712,955 and U.S. Pat. No. 6,299,760; Ni/Mo/W/maleate is acatalyst precursor made per example 1 and sulfided as per example 6;Mg—Ni—Mo—W maleate catalyst_precursor is a catalyst precursor made perexample 21 (with a diluent) and then sulfided per example 23(sulfidation with DMDS gas phase).

The results are presented in Table 7.

TABLE 7 Mg/Ni/Mo/ Ni/Mo/ Ni/Mo/W/ W/Si/Al Feedstock alumina Ni/Mo/Wmaleate maleate 700 F.+ conversion (wt-%/wt-%) 34.1 30.0 30.0 33.8Temperature (° F.) 725 700 690 700 No Loss yields, Wt % C4 minus 0.0 1.10.9 0.5 1.0 C5-180° F. 0.0 1.0 0.7 1.6 1.0 180-700° F. 6.5 36.2 32.7732.05 35.83 700° F.+ 93.5 62.2 66.0 64.1 65.1 Sulfur, 2.7E+04 7.5 8.3 80.01 ppm in 700° F.⁺ Nitrogen, 1.2E+03 <0.25 1.2 1 1.45 ppm in 700° F.⁺

As shown in the table, when the Group VIII metal was nickel, theaddition of IIA metal (magnesia) and the silica-alumina to the synthesisof the catalyst precursor improved the catalytic activity bysignificantly lowering the sulfur in the fration boiling above 700° F.at about 30% 700° F. conversion from 7.5 (conventional Ni—Mo-alumina) or8.3 (Ni—Mo—W prior art) or 8 (Ni—Mo—W-maleate catalyst precursor ofExample 1) to 0.01 ppm (Mg/Ni/Mo/W/Si/Al maleate catalyst precursor ofExample 20).

Example 25

A catalyst based on the Ni—Mo—W-maleate catalyst precursor of Example 1and sulfided with DMDS gas per example 6 was evaluated in ahydroconversion process. The evaluation included hydrocracking, HDS, andHDN activity using a vacuum gas oil (VGO) feedstock with a boiling pointabove 700° F., a sulfur content of 31135 ppm, a nitrogen content of31230 ppm, and other properties as presented in Table 1. The reactorconditions were at a H₂ gas rate of 5000 SCFB, and an LHSV of 0.75, 700°F. Under a hydrogen partial pressure of about 550 psig, the catalystremoved at least 70% of the nitrogen removed under comparableconditions, but at hydrogen partial pressure of about 2100 psig.

Example 26

Example 24 is repeated, except that the hydrogen partial pressure wasabout 450 psig. Even at a lower hydrogen partial pressure, themulti-metallic catalyst still removed at least 70% of the nitrogenremoved at hydrogen partial pressure of about 2100 psig, with otherprocess parameters being comparable.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the following specification andattached claims are approximations that can vary depending upon thedesired properties sought to be obtained by the present invention. It isnoted that, as used in this specification and the appended claims, thesingular forms “a,” “an,” and “the,” include plural references unlessexpressly and unequivocally limited to one referent. As used herein, theterm “include” and its grammatical variants are intended to benon-limiting, such that recitation of items in a list is not to theexclusion of other like items that can be substituted or added to thelisted items.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. The patentable scope is defined bythe claims, and can include other examples that occur to those skilledin the art. Such other examples are intended to be within the scope ofthe claims if they have structural elements that do not differ from theliteral language of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal languages ofthe claims. All citations referred herein are expressly incorporatedherein by reference.

TABLE 4 System I II Run Hours 504 600 1008 480 504 888 Total Pressure,PSIG 1509 1512 1536 1509 1528 1506 LHSV/WHSV, h-1 1.0/1.27 1.0/1.271.0/1.27 1.01/1.24 1.01/1.24 1.01/1.24 Gas Rate, SCFB 5381 5389 53685349 5343 5367 C.A.T., F. 751 752 766 731 731 741 No-loss Yields, wt %C1 0.29 0.29 0.33 0.20 0.20 0.25 C2 0.22 0.22 0.23 0.12 0.12 0.17 C30.31 0.29 0.31 0.18 0.18 0.24 i-C4 0.08 0.08 0.08 0.04 0.04 0.07 n-C40.25 0.22 0.25 0.14 0.14 0.17 C5-180 F. 0.99 0.90 0.80 0.46 0.46 0.47180-250 F. 0.60 0.54 0.70 0.08 0.08 0.25 250-550 F. 18.01 17.05 20.2415.38 15.17 16.44 550-700 F. 34.47 34.04 34.65 34.69 34.45 34.04 700 F.+44.60 45.96 42.07 48.16 48.59 47.40 H2 Consumption, SCFB 820 — 724 732726 — WLP Nitrogen, ppm 17.0 19.9 17.4 17.6 19.3 18.8 Sulfur, ppm 5.87.3 5.9 6.8 7.2 9.3 Stripper Bottoms API gravity 27.8 27.5 28.0 27.427.4 27.3 Nitrogen, ppm 17.5 20.4 18.0 17.7 19.4 19.1 Sulfur, ppm 5.97.5 6.04 6.9 7.3 9.5 PNA analyses Aromatics, vol % 35.2 35.6 37.9 32.933.7 35.3 Naphthenes, vol % 54.9 54.4 53.0 56.1 55.7 55.0 Paraffins, vol% 8.3 8.3 8.3 9.2 8.9 8.1 Cut Point, ° F. 361 366 352 359 359 352Closure, wt % 100.59 99.35 97.79 98.01 96.32 97.51

1. A catalyst composition prepared by sulfiding an unsupported catalystprecursor composition obtained by co-precipitating at reactionconditions to form a precipitate: at least a metal compound in solutionselected from Group VIII and combinations thereof; at least two GroupVIB metal compounds in solution; and at least one organic oxygencontaining chelating ligand in solution; wherein the Group VIII metal isnickel and the at least two Group VIB metal compounds are molybdenum andtungsten, and wherein the catalyst has a fouling rate of less than 8° F.(4.4° C.) per 1000 hour when used as a sole catalyst; and wherein theunsupported catalyst precursor composition is formed without addition ofany sulfur compounds to the co-precipitating reaction to form theprecipitate.
 2. The catalyst composition of claim 1, wherein thecatalyst has a fouling rate of less than 5° F. (2.8° C.) per 1000 hour.3. The catalyst composition of claim 2, wherein the catalyst has afouling rate of less than 2.5° F. (1.4° C.) per 1000 hour.
 4. Thecatalyst composition of claim 1, wherein the catalyst is employed in afixed bed hydroprocessing system having at least two layers ofcatalysts, and wherein the layered catalyst system has a fouling rate ofless than 30° F. (16.7° C.) per 1000 hour, and wherein the catalystcomprises from 10 - 80 vol. % of the layered catalyst system.
 5. Thecatalyst composition of claim 4, wherein the layered catalyst system hasa fouling rate of less than 26° F. (14.4° C.) per 1000 hour, and whereinthe catalyst comprises at least 25 vol. % of the layered catalystsystem.
 6. The catalyst composition of claim 5, wherein the layeredcatalyst system has a fouling rate of less than 19° F. (10.6° C.) per1000 hour, and wherein the catalyst comprises at least 35 vol. % of thelayered catalyst system.
 7. The catalyst composition of claim 6, whereinthe layered catalyst system has a fouling rate of less than 10° F. (5.6°C.) per 1000 hour, and wherein the catalyst comprises at least 50 vol. %of the layered catalyst system.
 8. The catalyst composition of claim 1,wherein the catalyst precursor composition is charge neutral, and of theformula A_(v)[(M^(P)) (OH)_(x) (L)^(n) _(y)](M^(VIB)O₄), wherein A is atleast one of an alkali metal cation, an ammonium, an organic ammoniumand a phosphonium cation, M^(P) is nickel with an oxidation state of +2L is at least one organic oxygen-containing ligand having a charge n<=0; M^(VIB) is selected from molybdenum, tungsten and combinationsthereof with an oxidation state of +6, M^(P): M^(VIB) has an atomicratio of 100:1 to 1:100; v −2 +P*z−x*z+n*y*z =0; and 0 ≦y≦−P/n; 0 ≦x≦P;0 ≦v≦2; 0 ≦z.
 9. The catalyst composition of claim 8, wherein theorganic oxygen containing ligand L has an LD50 rate of >700 mg/Kg. 10.The catalyst composition of claim 8, wherein the oxygen-containingchelating agent L is an organic acid addition salt.
 11. The catalystcomposition of claim 8, wherein the oxygen-containing chelating agent Lin the catalyst precursor is selected from the group of formic acid,acetic acid, propionic acid, maleic acid, fumaric acid, succinic acid,tartaric acid, citric acid, oxalic acid, glyoxylic acid, aspartic acid,alkane sulfonic acids such as methane sulfonic acid and ethane sulfonicacid, aryl sulfonic acid, and arylcarboxylic acid.
 12. The catalystcomposition of claim 8, wherein the organic, oxygen-containing chelatingligand L is selected from the group of glycolic acid, lactic acid,tartaric acid, malic acid, citric acid, gluconic acid, methoxy-aceticacid, ethoxy-acetic acid, malonic acid, succinic acid, and glyoxylic.13. The catalyst composition of claim 8, wherein the oxygen-containingchelating is an organic sulfur compound.
 14. The catalyst composition ofclaim 1, wherein the oxygen-containing chelating agent L is selectedfrom mercapto-succinic acid and thio-diglycolic acid.
 15. The catalystcomposition of claim 1, wherein the at least a group VIII to the atleast two group VIB molar ratio ranges from 10:1 to 1:10.
 16. Thecatalyst composition of claim 1, wherein the catalyst precursor ismesoporous with an average pore volume between 0.1 and 0.2 cc/g.
 17. Thecatalyst composition of claim 1, wherein the catalyst precursor has anaverage surface area between about 10 and 200 m²/g as measured by BJHanalysis under B.E.T. nitrogen adsorption conditions.
 18. The catalystcomposition of claim 1, wherein the unsupported catalyst precursorcomposition is formed without addition of any inorganic oxides orinorganic acids to the co-precipitating reaction to form theprecipitate.